CWE-407
Allowed-with-ReviewInefficient Algorithmic Complexity
Abstraction: Class · Status: Incomplete
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
313 vulnerabilities reference this CWE, most recent first.
GHSA-7X8H-JG2X-PJM5
Vulnerability from github – Published: 2026-09-07 15:33 – Updated: 2026-09-07 15:33The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
{
"affected": [],
"aliases": [
"CVE-2026-86429"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-07T13:20:42Z",
"severity": "HIGH"
},
"details": "The league/commonmark (thephpleague/commonmark) library in versions \u003e= 1.5.0 and \u003c 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents \u2014 such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes \u2014 to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.",
"id": "GHSA-7x8h-jg2x-pjm5",
"modified": "2026-09-07T15:33:53Z",
"published": "2026-09-07T15:33:53Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-jjv6-8j6v-6j52"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86429"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/commonmark-before-2.9.1-denial-of-service-via-smartpunct-and-attributes"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-8344-3JMQ-59R6
Vulnerability from github – Published: 2026-09-08 21:01 – Updated: 2026-09-08 21:01Summary
xmldom builds the attribute collection of every parsed element by inserting attributes one at a
time into a DOM NamedNodeMap. Each insertion first performs a linear scan of all
already-inserted attributes to enforce the DOM uniqueness rule (no two attributes with the same
qualified name / namespace+local-name). Parsing an element that carries M distinct attributes
therefore costs 1 + 2 + … + M = O(M²) comparisons.
Because the trigger is simply "one element with many attributes", the attack payload is a
fully well-formed XML document. No malformed markup, no error recovery, and no non-default
parser options are involved — parsing completes silently with zero warning/error/fatalError
events. An attacker who can submit a modest, highly compressible document (a single element with
tens of thousands of attributes, ~340 KB uncompressed) can consume seconds of single-threaded CPU
per request, enabling an unauthenticated denial of service.
This is distinct from the known quadratic-memory namespace-map issue: it burns CPU and it does not require any namespace declarations or nesting.
Details
The DOM content handler adds each attribute of a starting element by calling
el.setAttributeNode(attr) in a loop:
// DOMHandler.startElement
for (var i = 0; i < len; i++) {
var namespaceURI = attrs.getURI(i);
var value = attrs.getValue(i);
var qName = attrs.getQName(i);
var attr = doc.createAttributeNS(namespaceURI, qName);
attr.value = attr.nodeValue = value;
el.setAttributeNode(attr); // O(existing attrs) each — see below
}
https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom-parser.js#L370-L387
setAttributeNode delegates to NamedNodeMap.setNamedItem, which calls getNamedItemNS to look
for an existing attribute with the same namespace URI and local name before appending:
setNamedItem: function (attr) {
var el = attr.ownerElement;
if (el && el !== this._ownerElement) {
throw new DOMException(DOMException.INUSE_ATTRIBUTE_ERR);
}
var oldAttr = this.getNamedItemNS(attr.namespaceURI, attr.localName); // linear scan
if (oldAttr === attr) {
return attr;
}
_addNamedNode(this._ownerElement, this, attr, oldAttr);
return oldAttr;
},
https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L612-L623
getNamedItemNS walks the whole list on every call:
getNamedItemNS: function (namespaceURI, localName) {
if (!namespaceURI) {
namespaceURI = null;
}
var i = 0;
while (i < this.length) {
var node = this[i];
if (node.localName === localName && node.namespaceURI === namespaceURI) {
return node;
}
i++;
}
return null;
},
https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L702-L715
For the i-th attribute the scan visits i-1 entries, so inserting M distinct attributes performs
Θ(M²) comparisons. There is no hash index or set keyed by name; the map is a plain
array-backed structure.
The same structure exists on 0.8.x. There setNamedItem dedups via
getNamedItem(attr.nodeName) instead of getNamedItemNS, but that method is likewise a full linear
scan, so the complexity is identical:
startElementloop /setAttributeNode: https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom-parser.js#L159-L176setNamedItem→ lineargetNamedItem: https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom.js#L286-L308
The linear-scan NamedNodeMap predates the @xmldom/xmldom fork and is present unchanged in the
unscoped xmldom package back to its earliest published release. In xmldom@0.1.0, parsing already
inserts each attribute one at a time (DOMHandler.startElement loops calling
setAttributeNS → setAttributeNode → NamedNodeMap.setNamedItem), and setNamedItem dedups by
calling getNamedItemNS, which is a full linear while (i--) scan of the already-inserted
attributes — the identical O(M²) structure. The whole unscoped line (0.1.0 … 0.6.0) is
therefore affected; the earliest published tag (0.1.0) was verified to contain the per-insert
linear dedup scan.
Proof of Concept
A single well-formed element with M distinct attributes. No malformed markup and no options:
'use strict';
var DOMParser = require('@xmldom/xmldom').DOMParser;
function buildDoc(m) {
var parts = new Array(m);
for (var i = 0; i < m; i++) parts[i] = 'a' + i + '="x"';
return '<r ' + parts.join(' ') + '/>'; // <r a0="x" a1="x" ... a{M-1}="x"/>
}
for (var _i = 0, sizes = [2000, 4000, 8000, 16000, 32000]; _i < sizes.length; _i++) {
var m = sizes[_i];
var xml = buildDoc(m);
var t0 = process.hrtime.bigint();
var doc = new DOMParser().parseFromString(xml, 'text/xml'); // silent: no error events
var ms = Number(process.hrtime.bigint() - t0) / 1e6;
console.log(m + ' attrs, ' + xml.length + ' bytes -> ' + ms.toFixed(1) + ' ms; parsed=' +
doc.documentElement.attributes.length);
}
Measured with Node.js v18.20.8 (wall-clock; absolute numbers vary by host, the scaling is the load-bearing fact):
@xmldom/xmldom 0.9.10:
| M (attributes) | input bytes | time (ms) | ratio vs prev |
|---|---|---|---|
| 2000 | 18,894 | 13.4 | — |
| 4000 | 38,894 | 38.7 | ×2.9 |
| 8000 | 78,894 | 100.8 | ×2.6 |
| 16000 | 164,894 | 406.2 | ×4.0 |
| 32000 | 340,894 | 2149.5 | ×5.3 |
@xmldom/xmldom 0.8.13:
| M (attributes) | input bytes | time (ms) |
|---|---|---|
| 2000 | 18,894 | 10.6 |
| 4000 | 38,894 | 19.9 |
| 8000 | 78,894 | 75.9 |
| 16000 | 164,894 | 657.7 |
| 32000 | 340,894 | 1643.2 |
xmldom (unscoped) 0.6.0: 4000 → 28.2 ms, 8000 → 131.8 ms, 16000 → 545.2 ms (≈ ×4 per doubling).
Time grows ≈ ×4 per doubling of M — quadratic. About 340 KB of well-formed input costs ~1.6–2.1 s
of single-threaded CPU, and it keeps scaling: doubling the attribute count quadruples the cost.
The document is trivially generated and compresses to a few kilobytes on the wire.
Impact
Unauthenticated, remotely triggerable denial of service against any service that parses attacker-influenced XML/HTML with xmldom. A single request holds one event-loop thread for seconds; a handful of concurrent requests can saturate CPU and stall the process. Because the payload is a plain well-formed document (one element, many attributes), it passes any "must be well-formed" gate and reaches the parser before any application-level validation (e.g. schema checks or signature verification) can run. The payload is highly compressible, so it is effective over compressed transports.
Fix Applied
Replaced the per-insert linear duplicate scan on the parse-time dedup path with a name-keyed
index, so de-duplicating an element's attributes during parse is O(M) instead of O(M²) — a
well-formed-but-hostile attribute list can no longer wedge the parse. Behavior-preserving: attribute
order and duplicate resolution (last value wins, first position kept) are byte-identical. Non-breaking
and independent of requireWellFormed; ships on both maintained versions.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.8.14"
},
"package": {
"ecosystem": "npm",
"name": "@xmldom/xmldom"
},
"ranges": [
{
"events": [
{
"introduced": "0.7.0"
},
{
"fixed": "0.8.15"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.9.11"
},
"package": {
"ecosystem": "npm",
"name": "@xmldom/xmldom"
},
"ranges": [
{
"events": [
{
"introduced": "0.9.0"
},
{
"fixed": "0.9.12"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "npm",
"name": "xmldom"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "0.6.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-83613"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-08T21:01:31Z",
"nvd_published_at": "2026-09-01T15:17:39Z",
"severity": "HIGH"
},
"details": "## Summary\n\nxmldom builds the attribute collection of every parsed element by inserting attributes one at a\ntime into a DOM `NamedNodeMap`. Each insertion first performs a **linear scan of all\nalready-inserted attributes** to enforce the DOM uniqueness rule (no two attributes with the same\nqualified name / namespace+local-name). Parsing an element that carries `M` distinct attributes\ntherefore costs `1 + 2 + \u2026 + M = O(M\u00b2)` comparisons.\n\nBecause the trigger is simply \"one element with many attributes\", the attack payload is a\n**fully well-formed XML document**. No malformed markup, no error recovery, and no non-default\nparser options are involved \u2014 parsing completes silently with zero `warning`/`error`/`fatalError`\nevents. An attacker who can submit a modest, highly compressible document (a single element with\ntens of thousands of attributes, ~340 KB uncompressed) can consume seconds of single-threaded CPU\nper request, enabling an unauthenticated denial of service.\n\nThis is distinct from the known quadratic-**memory** namespace-map issue: it burns **CPU** and it\ndoes not require any namespace declarations or nesting.\n\n## Details\n\nThe DOM content handler adds each attribute of a starting element by calling\n`el.setAttributeNode(attr)` in a loop:\n\n```js\n// DOMHandler.startElement\nfor (var i = 0; i \u003c len; i++) {\n\tvar namespaceURI = attrs.getURI(i);\n\tvar value = attrs.getValue(i);\n\tvar qName = attrs.getQName(i);\n\tvar attr = doc.createAttributeNS(namespaceURI, qName);\n\tattr.value = attr.nodeValue = value;\n\tel.setAttributeNode(attr); // O(existing attrs) each \u2014 see below\n}\n```\n\nhttps://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom-parser.js#L370-L387\n\n`setAttributeNode` delegates to `NamedNodeMap.setNamedItem`, which calls `getNamedItemNS` to look\nfor an existing attribute with the same namespace URI and local name before appending:\n\n```js\nsetNamedItem: function (attr) {\n\tvar el = attr.ownerElement;\n\tif (el \u0026\u0026 el !== this._ownerElement) {\n\t\tthrow new DOMException(DOMException.INUSE_ATTRIBUTE_ERR);\n\t}\n\tvar oldAttr = this.getNamedItemNS(attr.namespaceURI, attr.localName); // linear scan\n\tif (oldAttr === attr) {\n\t\treturn attr;\n\t}\n\t_addNamedNode(this._ownerElement, this, attr, oldAttr);\n\treturn oldAttr;\n},\n```\n\nhttps://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L612-L623\n\n`getNamedItemNS` walks the whole list on every call:\n\n```js\ngetNamedItemNS: function (namespaceURI, localName) {\n\tif (!namespaceURI) {\n\t\tnamespaceURI = null;\n\t}\n\tvar i = 0;\n\twhile (i \u003c this.length) {\n\t\tvar node = this[i];\n\t\tif (node.localName === localName \u0026\u0026 node.namespaceURI === namespaceURI) {\n\t\t\treturn node;\n\t\t}\n\t\ti++;\n\t}\n\treturn null;\n},\n```\n\nhttps://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L702-L715\n\nFor the i-th attribute the scan visits `i-1` entries, so inserting `M` distinct attributes performs\n`\u0398(M\u00b2)` comparisons. There is no hash index or set keyed by name; the map is a plain\narray-backed structure.\n\nThe same structure exists on 0.8.x. There `setNamedItem` dedups via\n`getNamedItem(attr.nodeName)` instead of `getNamedItemNS`, but that method is likewise a full linear\nscan, so the complexity is identical:\n\n- `startElement` loop / `setAttributeNode`:\n https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom-parser.js#L159-L176\n- `setNamedItem` \u2192 linear `getNamedItem`:\n https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom.js#L286-L308\n\nThe linear-scan `NamedNodeMap` predates the `@xmldom/xmldom` fork and is present unchanged in the\nunscoped `xmldom` package back to its earliest published release. In `xmldom@0.1.0`, parsing already\ninserts each attribute one at a time (`DOMHandler.startElement` loops calling\n`setAttributeNS` \u2192 `setAttributeNode` \u2192 `NamedNodeMap.setNamedItem`), and `setNamedItem` dedups by\ncalling `getNamedItemNS`, which is a full linear `while (i--)` scan of the already-inserted\nattributes \u2014 the identical `O(M\u00b2)` structure. The whole unscoped line (`0.1.0` \u2026 `0.6.0`) is\ntherefore affected; the earliest published tag (`0.1.0`) was verified to contain the per-insert\nlinear dedup scan.\n\n## Proof of Concept\n\nA single well-formed element with `M` distinct attributes. No malformed markup and no options:\n\n```js\n\u0027use strict\u0027;\nvar DOMParser = require(\u0027@xmldom/xmldom\u0027).DOMParser;\n\nfunction buildDoc(m) {\n\tvar parts = new Array(m);\n\tfor (var i = 0; i \u003c m; i++) parts[i] = \u0027a\u0027 + i + \u0027=\"x\"\u0027;\n\treturn \u0027\u003cr \u0027 + parts.join(\u0027 \u0027) + \u0027/\u003e\u0027; // \u003cr a0=\"x\" a1=\"x\" ... a{M-1}=\"x\"/\u003e\n}\n\nfor (var _i = 0, sizes = [2000, 4000, 8000, 16000, 32000]; _i \u003c sizes.length; _i++) {\n\tvar m = sizes[_i];\n\tvar xml = buildDoc(m);\n\tvar t0 = process.hrtime.bigint();\n\tvar doc = new DOMParser().parseFromString(xml, \u0027text/xml\u0027); // silent: no error events\n\tvar ms = Number(process.hrtime.bigint() - t0) / 1e6;\n\tconsole.log(m + \u0027 attrs, \u0027 + xml.length + \u0027 bytes -\u003e \u0027 + ms.toFixed(1) + \u0027 ms; parsed=\u0027 +\n\t\tdoc.documentElement.attributes.length);\n}\n```\n\nMeasured with Node.js v18.20.8 (wall-clock; absolute numbers vary by host, the **scaling** is the\nload-bearing fact):\n\n**`@xmldom/xmldom` 0.9.10:**\n\n| M (attributes) | input bytes | time (ms) | ratio vs prev |\n|---:|---:|---:|---:|\n| 2000 | 18,894 | 13.4 | \u2014 |\n| 4000 | 38,894 | 38.7 | \u00d72.9 |\n| 8000 | 78,894 | 100.8 | \u00d72.6 |\n| 16000 | 164,894 | 406.2 | \u00d74.0 |\n| 32000 | 340,894 | 2149.5 | \u00d75.3 |\n\n**`@xmldom/xmldom` 0.8.13:**\n\n| M (attributes) | input bytes | time (ms) |\n|---:|---:|---:|\n| 2000 | 18,894 | 10.6 |\n| 4000 | 38,894 | 19.9 |\n| 8000 | 78,894 | 75.9 |\n| 16000 | 164,894 | 657.7 |\n| 32000 | 340,894 | 1643.2 |\n\n**`xmldom` (unscoped) 0.6.0:** 4000 \u2192 28.2 ms, 8000 \u2192 131.8 ms, 16000 \u2192 545.2 ms (\u2248 \u00d74 per doubling).\n\nTime grows \u2248 \u00d74 per doubling of `M` \u2014 quadratic. About **340 KB of well-formed input costs ~1.6\u20132.1 s\nof single-threaded CPU**, and it keeps scaling: doubling the attribute count quadruples the cost.\nThe document is trivially generated and compresses to a few kilobytes on the wire.\n\n## Impact\n\nUnauthenticated, remotely triggerable denial of service against any service that parses\nattacker-influenced XML/HTML with xmldom. A single request holds one event-loop thread for seconds;\na handful of concurrent requests can saturate CPU and stall the process. Because the payload is a\nplain well-formed document (one element, many attributes), it passes any \"must be well-formed\" gate\nand reaches the parser before any application-level validation (e.g. schema checks or signature\nverification) can run. The payload is highly compressible, so it is effective over compressed\ntransports.\n\n## Fix Applied\n\nReplaced the per-insert linear duplicate scan on the parse-time dedup path with a name-keyed\nindex, so de-duplicating an element\u0027s attributes during parse is O(M) instead of O(M\u00b2) \u2014 a\nwell-formed-but-hostile attribute list can no longer wedge the parse. Behavior-preserving: attribute\norder and duplicate resolution (last value wins, first position kept) are byte-identical. Non-breaking\nand independent of `requireWellFormed`; ships on both maintained versions.",
"id": "GHSA-8344-3jmq-59r6",
"modified": "2026-09-08T21:01:31Z",
"published": "2026-09-08T21:01:31Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-8344-3jmq-59r6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83613"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/pull/1071"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/pull/1072"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/commit/2c548f200cfec991cd5846627ef8f03542309213"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/commit/cfb09b5dbeb035fdfedc9f01e2bbaf226bf47cf3"
},
{
"type": "PACKAGE",
"url": "https://github.com/xmldom/xmldom"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/releases/tag/0.8.15"
},
{
"type": "WEB",
"url": "https://github.com/xmldom/xmldom/releases/tag/0.9.12"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "xmldom: Quadratic-time attribute deduplication"
}
GHSA-8CJ2-994R-9FPQ
Vulnerability from github – Published: 2026-07-27 12:31 – Updated: 2026-07-27 21:31Inefficient Algorithmic Complexity, Allocation of Resources Without Limits or Throttling vulnerability in Apache Thrift Node.js bindings.
This issue affects Apache Thrift: before 0.24.0.
Users are recommended to upgrade to version 0.24.0, which fixes the issue.
{
"affected": [],
"aliases": [
"CVE-2026-55968"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-27T12:16:45Z",
"severity": "HIGH"
},
"details": "Inefficient Algorithmic Complexity, Allocation of Resources Without Limits or Throttling vulnerability in Apache Thrift Node.js bindings.\n\nThis issue affects Apache Thrift: before 0.24.0.\n\nUsers are recommended to upgrade to version 0.24.0, which fixes the issue.",
"id": "GHSA-8cj2-994r-9fpq",
"modified": "2026-07-27T21:31:21Z",
"published": "2026-07-27T12:31:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55968"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread/7v3jhgwfbmhx42424phydlnzb109g8b9"
},
{
"type": "WEB",
"url": "https://lists.apache.org/thread/gxhhfyr6flr5vzr4qnxm13p6fc41qstp"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2026/07/24/39"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-8F6W-8H24-FW66
Vulnerability from github – Published: 2026-05-20 12:30 – Updated: 2026-05-21 00:30NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code path to consult the negative cache for DS records does not take into account the limit on NSEC3 hash calculations introduced in 1.19.1. This leads to degradation of service during the attack. An adversary that controls a DNSSEC signed zone can exploit this by signing NSEC3 records with acceptably high iterations for child delegations and querying a vulnerable Unbound. Unbound will keep performing the allowed hash calculations on the NSEC3 records and will not limit the work by the mitigation introduced in 1.19.1. As a side effect, a global lock for the negative cache will be held for the duration of the hashing, blocking other threads that need to consult the negative cache. Coordinated attacks could raise the vulnerability to denial of service. Unbound 1.25.1 contains a patch with a fix to bound the vulnerable code path with the existing limit for NSEC3 hash calculations.
{
"affected": [],
"aliases": [
"CVE-2026-42923"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-20T10:16:27Z",
"severity": "MODERATE"
},
"details": "NLnet Labs Unbound up to and including version 1.25.0 has a vulnerability in the DNSSEC validator where the code path to consult the negative cache for DS records does not take into account the limit on NSEC3 hash calculations introduced in 1.19.1. This leads to degradation of service during the attack. An adversary that controls a DNSSEC signed zone can exploit this by signing NSEC3 records with acceptably high iterations for child delegations and querying a vulnerable Unbound. Unbound will keep performing the allowed hash calculations on the NSEC3 records and will not limit the work by the mitigation introduced in 1.19.1. As a side effect, a global lock for the negative cache will be held for the duration of the hashing, blocking other threads that need to consult the negative cache. Coordinated attacks could raise the vulnerability to denial of service. Unbound 1.25.1 contains a patch with a fix to bound the vulnerable code path with the existing limit for NSEC3 hash calculations.",
"id": "GHSA-8f6w-8h24-fw66",
"modified": "2026-05-21T00:30:27Z",
"published": "2026-05-20T12:30:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42923"
},
{
"type": "WEB",
"url": "https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42923.txt"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber",
"type": "CVSS_V4"
}
]
}
GHSA-8G4Q-XG66-9FP4
Vulnerability from github – Published: 2024-10-08 20:25 – Updated: 2024-10-24 16:11Microsoft Security Advisory CVE-2024-43485 | .NET Denial of Service Vulnerability
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in System.Text.Json 6.0.x and 8.0.x. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
In System.Text.Json 6.0.x and 8.0.x, applications which deserialize input to a model with an [JsonExtensionData] property can be vulnerable to an algorithmic complexity attack resulting in Denial of Service.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/329
Mitigation factors
JSON models which do not utilize the [JsonExtensionData] feature are not impacted by this vulnerability.
Affected software
- Any .NET 8.0 application running on .NET 8.0.8 or earlier.
- Any .NET 6.0 aplication running on .NET 6.0.33 or earlier.
- Any application consuming one of the vulnerable packages.
Affected Packages
The vulnerability affects any Microsoft .NET Core project if it uses any of affected packages versions listed below
.NET 8
| Package name | Affected version | Patched version |
|---|---|---|
| System.Text.Json | >= 8.0.0, <= 8.0.4 | 8.0.5 |
.NET 6
| Package name | Affected version | Patched version |
|---|---|---|
| System.Text.Json | >= 6.0.0, <= 6.0.9 | 6.0.10 |
Advisory FAQ
How do I know if I am affected?
If you have a runtime or SDK with a version listed, or an affected package listed in affected software or affected packages, you're exposed to the vulnerability.
How do I fix the issue?
- To fix the issue please install the latest version of .NET 8.0 or .NET 6.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
- .NET Framework-based applications and other application types need to perform a package update.
- If you have .NET 6.0 or greater installed, you can list the versions you have installed by running the
dotnet --infocommand. You will see output like the following;
.NET Core SDK (reflecting any global.json):
Version: 8.0.200
Commit: 8473146e7d
Runtime Environment:
OS Name: Windows
OS Version: 10.0.18363
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\6.0.300\
Host (useful for support):
Version: 8.0.3
Commit: 8473146e7d
.NET Core SDKs installed:
8.0.200 [C:\Program Files\dotnet\sdk]
.NET Core runtimes installed:
Microsoft.AspAspNetCore.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspAspNetCore.App]
Microsoft.AspNetCore.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.WindowsDesktop.App 8.0.3 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
To install additional .NET Core runtimes or SDKs:
https://aka.ms/dotnet-download
- If you're using .NET 6.0, you should download and install .NET 6.0.35 Runtime or .NET 6.0.135 SDK (for Visual Studio 2022 v17.6) from https://dotnet.microsoft.com/download/dotnet-core/6.0.
- If you're using .NET 8.0, you should download and install .NET 8.0.10 Runtime or .NET 8.0.110 SDK (for Visual Studio 2022 v17.8) from https://dotnet.microsoft.com/download/dotnet-core/8.0.
.NET 8.0 and .NET 6.0 updates are also available from Microsoft Update. To access this either type "Check for updates" in your Windows search, or open Settings, choose Update & Security and then click Check for Updates.
Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.
Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.
Other Information
Reporting Security Issues
If you have found a potential security issue in .NET 8.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core & .NET 5 Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.
Support
You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime and https://github.com/dotnet/aspnet/. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.
Disclaimer
The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
External Links
Revisions
V1.0 (October 08, 2024): Advisory published.
Version 1.0
Last Updated 2024-10-08
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 8.0.4"
},
"package": {
"ecosystem": "NuGet",
"name": "System.Text.Json"
},
"ranges": [
{
"events": [
{
"introduced": "8.0.0"
},
{
"fixed": "8.0.5"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 6.0.9"
},
"package": {
"ecosystem": "NuGet",
"name": "System.Text.Json"
},
"ranges": [
{
"events": [
{
"introduced": "6.0.0"
},
{
"fixed": "6.0.10"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-43485"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2024-10-08T20:25:19Z",
"nvd_published_at": "2024-10-08T18:15:10Z",
"severity": "HIGH"
},
"details": "# Microsoft Security Advisory CVE-2024-43485 | .NET Denial of Service Vulnerability\n\n## \u003ca name=\"executive-summary\"\u003e\u003c/a\u003eExecutive summary\n\nMicrosoft is releasing this security advisory to provide information about a vulnerability in System.Text.Json 6.0.x and 8.0.x. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.\n\nIn System.Text.Json 6.0.x and 8.0.x, applications which deserialize input to a model with an `[JsonExtensionData]` property can be vulnerable to an algorithmic complexity attack resulting in Denial of Service.\n\n## Announcement\n\nAnnouncement for this issue can be found at https://github.com/dotnet/announcements/issues/329\n\n## \u003ca name=\"mitigation-factors\"\u003e\u003c/a\u003eMitigation factors\n\nJSON models which do not utilize the `[JsonExtensionData]` feature are not impacted by this vulnerability.\n\n## \u003ca name=\"affected-software\"\u003e\u003c/a\u003eAffected software\n\n* Any .NET 8.0 application running on .NET 8.0.8 or earlier.\n* Any .NET 6.0 aplication running on .NET 6.0.33 or earlier.\n* Any application consuming one of the [vulnerable packages](affected-packages).\n\n## \u003ca name=\"affected-packages\"\u003e\u003c/a\u003eAffected Packages\nThe vulnerability affects any Microsoft .NET Core project if it uses any of affected packages versions listed below\n\n\n### \u003ca name=\".NET 8\"\u003e\u003c/a\u003e.NET 8\nPackage name | Affected version | Patched version\n------------ | ---------------- | -------------------------\n[System.Text.Json](https://www.nuget.org/packages/System.Text.Json) | \u003e= 8.0.0, \u003c= 8.0.4 | 8.0.5\n\n### \u003ca name=\".NET 6\"\u003e\u003c/a\u003e.NET 6\nPackage name | Affected version | Patched version\n------------ | ---------------- | -------------------------\n[System.Text.Json](https://www.nuget.org/packages/System.Text.Json) | \u003e= 6.0.0, \u003c= 6.0.9 | 6.0.10\n\n\n## Advisory FAQ\n\n### \u003ca name=\"how-affected\"\u003e\u003c/a\u003eHow do I know if I am affected?\n\nIf you have a runtime or SDK with a version listed, or an affected package listed in [affected software](#affected-packages) or [affected packages](#affected-software), you\u0027re exposed to the vulnerability.\n\n### \u003ca name=\"how-fix\"\u003e\u003c/a\u003eHow do I fix the issue?\n\n* To fix the issue please install the latest version of .NET 8.0 or .NET 6.0. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.\n* .NET Framework-based applications and other application types need to perform a package update.\n* If you have .NET 6.0 or greater installed, you can list the versions you have installed by running the `dotnet --info` command. You will see output like the following;\n\n```\n.NET Core SDK (reflecting any global.json):\n\n\n Version: 8.0.200\n Commit: 8473146e7d\n\nRuntime Environment:\n\n OS Name: Windows\n OS Version: 10.0.18363\n OS Platform: Windows\n RID: win10-x64\n Base Path: C:\\Program Files\\dotnet\\sdk\\6.0.300\\\n\nHost (useful for support):\n\n Version: 8.0.3\n Commit: 8473146e7d\n\n.NET Core SDKs installed:\n\n 8.0.200 [C:\\Program Files\\dotnet\\sdk]\n\n.NET Core runtimes installed:\n\n Microsoft.AspAspNetCore.App 8.0.3 [C:\\Program Files\\dotnet\\shared\\Microsoft.AspAspNetCore.App]\n Microsoft.AspNetCore.App 8.0.3 [C:\\Program Files\\dotnet\\shared\\Microsoft.AspNetCore.App]\n Microsoft.WindowsDesktop.App 8.0.3 [C:\\Program Files\\dotnet\\shared\\Microsoft.WindowsDesktop.App]\n\n\nTo install additional .NET Core runtimes or SDKs:\n https://aka.ms/dotnet-download\n```\n\n* If you\u0027re using .NET 6.0, you should download and install .NET 6.0.35 Runtime or .NET 6.0.135 SDK (for Visual Studio 2022 v17.6) from https://dotnet.microsoft.com/download/dotnet-core/6.0.\n* If you\u0027re using .NET 8.0, you should download and install .NET 8.0.10 Runtime or .NET 8.0.110 SDK (for Visual Studio 2022 v17.8) from https://dotnet.microsoft.com/download/dotnet-core/8.0.\n\n.NET 8.0 and .NET 6.0 updates are also available from Microsoft Update. To access this either type \"Check for updates\" in your Windows search, or open Settings, choose Update \u0026 Security and then click Check for Updates.\n\nOnce you have installed the updated runtime or SDK, restart your apps for the update to take effect.\n\nAdditionally, if you\u0027ve deployed [self-contained applications](https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd) targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.\n\n## Other Information\n\n### Reporting Security Issues\n\nIf you have found a potential security issue in .NET 8.0 or .NET 6.0, please email details to secure@microsoft.com. Reports may qualify for the Microsoft .NET Core \u0026 .NET 5 Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at \u003chttps://aka.ms/corebounty\u003e.\n\n### Support\n\nYou can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime and https://github.com/dotnet/aspnet/. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.\n\n### Disclaimer\n\nThe information provided in this advisory is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.\n\n### External Links\n\n[CVE-2024-43485]( https://www.cve.org/CVERecord?id=CVE-2024-43485)\n\n### Revisions\n\nV1.0 (October 08, 2024): Advisory published.\n\n_Version 1.0_\n\n_Last Updated 2024-10-08_",
"id": "GHSA-8g4q-xg66-9fp4",
"modified": "2024-10-24T16:11:22Z",
"published": "2024-10-08T20:25:19Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dotnet/runtime/security/advisories/GHSA-8g4q-xg66-9fp4"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-43485"
},
{
"type": "WEB",
"url": "https://github.com/dotnet/announcements/issues/329"
},
{
"type": "WEB",
"url": "https://github.com/dotnet/runtime/issues/108678"
},
{
"type": "PACKAGE",
"url": "https://github.com/dotnet/runtime"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-43485"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Microsoft Security Advisory CVE-2024-43485 | .NET Denial of Service Vulnerability"
}
GHSA-8H74-W38M-J62J
Vulnerability from github – Published: 2026-09-07 15:33 – Updated: 2026-09-07 15:33commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.
{
"affected": [],
"aliases": [
"CVE-2026-86428"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-07T13:20:42Z",
"severity": "HIGH"
},
"details": "commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.",
"id": "GHSA-8h74-w38m-j62j",
"modified": "2026-09-07T15:33:53Z",
"published": "2026-09-07T15:33:53Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86428"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/commonmark-1.5.0-before-2.10.0-denial-of-service-via-attributes"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-8PPF-4F7H-5PPJ
Vulnerability from github – Published: 2026-07-21 19:11 – Updated: 2026-07-21 19:11Impact
The BER/CER/DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs. A small crafted payload (tens of kilobytes) containing an OID with many arcs consumes seconds of CPU per decode() call, allowing denial of service in any application that decodes untrusted ASN.1 data (certificates, LDAP, SNMP, Kerberos, etc.). The corresponding encoders have the same quadratic behavior, reachable when an application re-encodes previously decoded attacker-supplied values.
The arc-size limit introduced for CVE-2026-23490 bounds the byte length of an individual arc but not the number of arcs, so it does not mitigate this issue.
Affected components
ObjectIdentifierPayloadDecoder and RelativeOIDPayloadDecoder in pyasn1/codec/ber/decoder.py; ObjectIdentifierEncoder and RelativeOIDEncoder in pyasn1/codec/ber/encoder.py. The CER and DER codecs inherit these and are equally affected.
Patches
Fixed in pyasn1 0.6.4: arc accumulation in both decoders and encoders now runs in linear time.
Workarounds
Limit the size of untrusted ASN.1 input before decoding.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.6.3"
},
"package": {
"ecosystem": "PyPI",
"name": "pyasn1"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.6.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-59885"
],
"database_specific": {
"cwe_ids": [
"CWE-400",
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2026-07-21T19:11:03Z",
"nvd_published_at": "2026-07-14T17:17:14Z",
"severity": "HIGH"
},
"details": "### Impact\nThe BER/CER/DER decoders process OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs. A small crafted payload (tens of kilobytes) containing an OID with many arcs consumes seconds of CPU per decode() call, allowing denial of service in any application that decodes untrusted ASN.1 data (certificates, LDAP, SNMP, Kerberos, etc.). The corresponding encoders have the same quadratic behavior, reachable when an application re-encodes previously decoded attacker-supplied values.\n\nThe arc-size limit introduced for CVE-2026-23490 bounds the byte length of an individual arc but not the number of arcs, so it does not mitigate this issue.\n\n### Affected components\nObjectIdentifierPayloadDecoder and RelativeOIDPayloadDecoder in pyasn1/codec/ber/decoder.py; ObjectIdentifierEncoder and RelativeOIDEncoder in pyasn1/codec/ber/encoder.py. The CER and DER codecs inherit these and are equally affected.\n\n### Patches\nFixed in pyasn1 0.6.4: arc accumulation in both decoders and encoders now runs in linear time.\n\n### Workarounds\nLimit the size of untrusted ASN.1 input before decoding.",
"id": "GHSA-8ppf-4f7h-5ppj",
"modified": "2026-07-21T19:11:03Z",
"published": "2026-07-21T19:11:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/pyasn1/pyasn1/security/advisories/GHSA-8ppf-4f7h-5ppj"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-59885"
},
{
"type": "WEB",
"url": "https://github.com/pyasn1/pyasn1/commit/45bdb19eb7df4b3780fe9c912c63e99bffc39dd9"
},
{
"type": "PACKAGE",
"url": "https://github.com/pyasn1/pyasn1"
},
{
"type": "WEB",
"url": "https://github.com/pyasn1/pyasn1/releases/tag/v0.6.4"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "pyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of service"
}
GHSA-8RR7-CVQ3-GMFH
Vulnerability from github – Published: 2026-09-01 20:28 – Updated: 2026-09-01 20:28Impact
AttributesExtension ships with the library but must be explicitly registered on the Environment; it is not included in CommonMarkConverter, GithubFlavoredMarkdownConverter, or GithubFlavoredMarkdownExtension. Applications that do not register AttributesExtension are not affected by this advisory.
Two paths in the extension re-process every attribute a node has already collected each time another attribute is applied to it. When the attributes carry distinct names, the collected set grows by one on every step and is walked again in full, so a run of n attributes costs O(n²).
1. Attribute nodes resolving to a common target (affected from 1.5.0).
AttributesListener::processDocument() merges each attribute node into the set accumulated for its target, then filters the result. Both operations traverse that entire set: AttributesHelper::mergeAttributes() rebuilds it with array_merge(), and AttributesHelper::filterAttributes() matches a regular expression against every name in it. A run of attribute nodes sharing one target therefore re-walks a set that grows by a key per node.
Two input shapes reach this path: adjacent inline attributes at the start of a block ({a0="v"}{a1="v"}…, where quoting the values is what keeps them separate — an unquoted value swallows the }{ that follows it), and a chain of attribute blocks held at their default target by reference definitions ({a0=v} / [a]: u / {a1=v} / [a]: u / …).
256 KB of adjacent inline attributes takes 20.0 seconds to convert, against 0.09 seconds once patched.
2. Consecutive attribute-block lines (affected from 2.0.0).
AttributesBlockContinueParser::tryContinue() merges each continuation line into the block's accumulated attributes, again rebuilding the whole set on every line. One distinct attribute per line ({a0=v} / {a1=v} / …) grows it by a key each time.
256 KB of such lines takes 1.9 seconds to convert while producing zero bytes of output, against 0.08 seconds once patched.
Relationship to GHSA-jjv6-8j6v-6j52. The fix released in 2.9.1 for that advisory made the class attribute cheap to accumulate, but left every other attribute name on the original path. Applications that upgraded to 2.9.1 or 2.9.2 remain exposed to this variant.
Overall impact. An unauthenticated attacker who can submit Markdown to an affected application can consume disproportionate CPU time with a comparatively small request, occupying PHP workers and preventing legitimate requests from completing. The impact is limited to availability: no data is disclosed, rendered output is unchanged, and no rendering restriction is bypassed.
Patches
The issue is patched in 2.10.0. Both paths now fold each node — or each line — into the accumulated attributes at a cost proportional to that node or line alone, rather than re-merging and re-filtering everything gathered so far. Rendered output is unchanged, down to the order in which attributes appear.
The listener path affects 1.5.0 through 2.9.2. The continuation-line path affects 2.0.0 through 2.9.2. The 1.x release line is no longer supported, so its users must upgrade to 2.10.0 or later.
Workarounds
If you cannot upgrade immediately:
- Do not register
AttributesExtensionwhen converting untrusted Markdown. This fully removes both paths. - If the extension is required, impose a strict maximum input length before conversion. Because the cost is quadratic, the cap must be small to meaningfully bound worst-case CPU time.
The attributes/allow allow-list added in 2.7.0 is not a mitigation. A non-empty allow-list happens to bound the first path, because unlisted names are discarded before they accumulate, but it does nothing for the second: continuation lines are merged while parsing, before any filtering takes place.
Restricting conversion to trusted users, applying strict execution-time limits, and rate-limiting requests reduce exposure but are not substitutes for upgrading.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "league/commonmark"
},
"ranges": [
{
"events": [
{
"introduced": "1.5.0"
},
{
"fixed": "2.10.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-1050",
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-01T20:28:40Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Impact\n\n`AttributesExtension` ships with the library but must be explicitly registered on the `Environment`; it is not included in `CommonMarkConverter`, `GithubFlavoredMarkdownConverter`, or `GithubFlavoredMarkdownExtension`. **Applications that do not register `AttributesExtension` are not affected by this advisory.**\n\nTwo paths in the extension re-process every attribute a node has already collected each time another attribute is applied to it. When the attributes carry distinct names, the collected set grows by one on every step and is walked again in full, so a run of *n* attributes costs O(n\u00b2).\n\n**1. Attribute nodes resolving to a common target (affected from 1.5.0).**\n\n`AttributesListener::processDocument()` merges each attribute node into the set accumulated for its target, then filters the result. Both operations traverse that entire set: `AttributesHelper::mergeAttributes()` rebuilds it with `array_merge()`, and `AttributesHelper::filterAttributes()` matches a regular expression against every name in it. A run of attribute nodes sharing one target therefore re-walks a set that grows by a key per node.\n\nTwo input shapes reach this path: adjacent inline attributes at the start of a block (`{a0=\"v\"}{a1=\"v\"}\u2026`, where quoting the values is what keeps them separate \u2014 an unquoted value swallows the `}{` that follows it), and a chain of attribute blocks held at their default target by reference definitions (`{a0=v}` / `[a]: u` / `{a1=v}` / `[a]: u` / \u2026).\n\n256 KB of adjacent inline attributes takes 20.0 seconds to convert, against 0.09 seconds once patched.\n\n**2. Consecutive attribute-block lines (affected from 2.0.0).**\n\n`AttributesBlockContinueParser::tryContinue()` merges each continuation line into the block\u0027s accumulated attributes, again rebuilding the whole set on every line. One distinct attribute per line (`{a0=v}` / `{a1=v}` / \u2026) grows it by a key each time.\n\n256 KB of such lines takes 1.9 seconds to convert while producing **zero bytes of output**, against 0.08 seconds once patched.\n\n**Relationship to GHSA-jjv6-8j6v-6j52.** The fix released in 2.9.1 for that advisory made the `class` attribute cheap to accumulate, but left every other attribute name on the original path. **Applications that upgraded to 2.9.1 or 2.9.2 remain exposed to this variant.**\n\n**Overall impact.** An unauthenticated attacker who can submit Markdown to an affected application can consume disproportionate CPU time with a comparatively small request, occupying PHP workers and preventing legitimate requests from completing. The impact is limited to availability: no data is disclosed, rendered output is unchanged, and no rendering restriction is bypassed.\n\n### Patches\n\nThe issue is patched in `2.10.0`. Both paths now fold each node \u2014 or each line \u2014 into the accumulated attributes at a cost proportional to that node or line alone, rather than re-merging and re-filtering everything gathered so far. Rendered output is unchanged, down to the order in which attributes appear.\n\nThe listener path affects `1.5.0` through `2.9.2`. The continuation-line path affects `2.0.0` through `2.9.2`. The 1.x release line is no longer supported, so its users must upgrade to `2.10.0` or later.\n\n### Workarounds\n\nIf you cannot upgrade immediately:\n\n- **Do not register `AttributesExtension`** when converting untrusted Markdown. This fully removes both paths.\n- If the extension is required, **impose a strict maximum input length before conversion**. Because the cost is quadratic, the cap must be small to meaningfully bound worst-case CPU time.\n\nThe `attributes/allow` allow-list added in 2.7.0 is **not** a mitigation. A non-empty allow-list happens to bound the first path, because unlisted names are discarded before they accumulate, but it does nothing for the second: continuation lines are merged while parsing, before any filtering takes place.\n\nRestricting conversion to trusted users, applying strict execution-time limits, and rate-limiting requests reduce exposure but are not substitutes for upgrading.",
"id": "GHSA-8rr7-cvq3-gmfh",
"modified": "2026-09-01T20:28:40Z",
"published": "2026-09-01T20:28:40Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/thephpleague/commonmark/security/advisories/GHSA-8rr7-cvq3-gmfh"
},
{
"type": "WEB",
"url": "https://github.com/thephpleague/commonmark/commit/f27eb720972490b5af4dbb635ad8634529faf9f2"
},
{
"type": "PACKAGE",
"url": "https://github.com/thephpleague/commonmark"
},
{
"type": "WEB",
"url": "https://github.com/thephpleague/commonmark/releases/tag/2.10.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "league/commonmark: Denial of service via distinctly-named attributes in the Attributes extension"
}
GHSA-8X48-8G7J-RQXP
Vulnerability from github – Published: 2026-08-27 18:32 – Updated: 2026-09-02 14:36Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-ww6m-cw3f-q94g. This link is maintained to preserve external references.
Original Description
nltk PorterStemmer in versions <= 3.10.2 (fixed in 3.10.3) contains an inefficient-algorithmic-complexity denial of service in PorterStemmer.stem(). The _is_consonant() helper walks backward over the entire run of trailing 'y' characters on every call, and _measure() invokes it for each stem position, causing O(n^2) behavior. A single ~20-50 KB untrusted token consisting of a long run of the letter 'y' followed by a matching suffix (e.g., 'ness') can pin a CPU core for seconds to minutes, causing availability impact.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "nltk"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "3.10.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-02T14:36:04Z",
"nvd_published_at": "2026-08-27T17:21:02Z",
"severity": "HIGH"
},
"details": "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of\u00a0GHSA-ww6m-cw3f-q94g. This link is maintained to preserve external references.\n\n## Original Description\nnltk PorterStemmer in versions \u003c= 3.10.2 (fixed in 3.10.3) contains an inefficient-algorithmic-complexity denial of service in PorterStemmer.stem(). The _is_consonant() helper walks backward over the entire run of trailing \u0027y\u0027 characters on every call, and _measure() invokes it for each stem position, causing O(n^2) behavior. A single ~20-50 KB untrusted token consisting of a long run of the letter \u0027y\u0027 followed by a matching suffix (e.g., \u0027ness\u0027) can pin a CPU core for seconds to minutes, causing availability impact.",
"id": "GHSA-8x48-8g7j-rqxp",
"modified": "2026-09-02T14:36:04Z",
"published": "2026-08-27T18:32:29Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/nltk/nltk/security/advisories/GHSA-ww6m-cw3f-q94g"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-81722"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/nltk-porterstemmer-before-3.10.3-quadratic-time-dos"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
],
"summary": "Duplicate Advisory: Quadratic-time DoS in PorterStemmer via long runs of \u0027y\u0027",
"withdrawn": "2026-09-02T14:36:04Z"
}
GHSA-93Q9-CRCW-VWGQ
Vulnerability from github – Published: 2025-11-28 09:30 – Updated: 2026-06-02 15:31In libexpat through 2.7.3, a crafted file with an approximate size of 2 MiB can lead to dozens of seconds of processing time.
{
"affected": [],
"aliases": [
"CVE-2025-66382"
],
"database_specific": {
"cwe_ids": [
"CWE-407"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-28T07:15:57Z",
"severity": "LOW"
},
"details": "In libexpat through 2.7.3, a crafted file with an approximate size of 2 MiB can lead to dozens of seconds of processing time.",
"id": "GHSA-93q9-crcw-vwgq",
"modified": "2026-06-02T15:31:50Z",
"published": "2025-11-28T09:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66382"
},
{
"type": "WEB",
"url": "https://github.com/libexpat/libexpat/issues/1076"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2025/12/02/1"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L",
"type": "CVSS_V3"
}
]
}
No mitigation information available for this CWE.
No CAPEC attack patterns related to this CWE.