Vulnerability-Lookup

GHSA-GJJ5-9665-RWRC

Vulnerability from github – Published: 2026-10-02 23:18 – Updated: 2026-10-02 23:18

Summary

probe-image-size: Quadratic-time Denial of Service in the SVG Parser

Details

Overview

probe-image-size scans the SVG header with a searching regular expression, /<[-_.:a-zA-Z0-9][^>]*>/. On input that contains many < characters but no >, the engine restarts the [^>]* scan at every < position and runs to end of input each time, giving quadratic time complexity.

Both the synchronous and the streaming parser are affected.

Impact

Every entry point that reaches the SVG parser is affected: probe.sync(), probe(stream) and probe(url). The URL form is the most exposed one — the input is fetched from a remote host, so an attacker only needs to supply a link.

Processing a crafted buffer blocks the Node.js event loop at 100% CPU for the whole duration. In production environments such as upload validators, image proxies or link unfurl services, a small number of concurrent requests is enough to deny service.

Root Cause Analysis

Two independent problems.

Absence of input size cap in the sync path. lib/parse_sync/svg.js copied the entire buffer into a string and matched against it. There was no size limit at all, so cost scaled with the size of the attacker-supplied buffer.
Repeated rescanning in the stream path. lib/parse_stream/svg.js did cap accumulated data at 64 KB, but called parseSvg(str) on the whole accumulated string on every chunk, giving O(chunks × N²). The cap does not help here: the more chunks the input is split into, the more times the quadratic scan is repeated.

Chunk size is influenced by the sender. highWaterMark (16 KB) is a buffering threshold, not a lower bound — a socket read returns whatever has arrived. A server that writes one byte at a time produces one-byte chunks; this was confirmed against the real needle pipeline with default options.

The original report identified (1) only, and stated that the 64 KB cap mitigates the streaming path. It does not.

Proof of Concept (PoC)

Synchronous:

const probe = require('probe-image-size')

// ~200 KB of '<a' — contains '<' but never '>'
probe.sync(Buffer.from('<a'.repeat(100000), 'latin1'))

Streaming — the same payload split into chunks, slower per byte than the synchronous form:

const { Readable } = require('stream')
const probe = require('probe-image-size')

const payload = Buffer.from('<a'.repeat(32768), 'latin1')
const chunks = []
for (let i = 0; i < payload.length; i += 4096) chunks.push(payload.subarray(i, i + 4096))

await probe(Readable.from(chunks))

Measurements on the maintainer's machine:

path	input	time
`probe.sync()`	25 KB	0.9 s
`probe.sync()`	50 KB	5.5 s
`probe.sync()`	100 KB	18 s
`probe.sync()`	200 KB	54 s
`probe(stream)`	64 KB, 1 chunk	1.6 s
`probe(stream)`	64 KB, 4 chunks	2.9 s
`probe(stream)`	64 KB, 16 chunks	9.6 s

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 7.3.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "probe-image-size"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.4.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-104861"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333",
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-02T23:18:02Z",
    "nvd_published_at": "2026-10-02T18:17:02Z",
    "severity": "HIGH"
  },
  "details": "## Overview\n\n`probe-image-size` scans the SVG header with a searching regular expression, `/\u003c[-_.:a-zA-Z0-9][^\u003e]*\u003e/`. On input that contains many `\u003c` characters but no `\u003e`, the engine restarts the `[^\u003e]*` scan at every `\u003c` position and runs to end of input each time, giving quadratic time complexity.\n\nBoth the synchronous and the streaming parser are affected.\n\n## Impact\n\nEvery entry point that reaches the SVG parser is affected: `probe.sync()`, `probe(stream)` and `probe(url)`. The URL form is the most exposed one \u2014 the input is fetched from a remote host, so an attacker only needs to supply a link.\n\nProcessing a crafted buffer blocks the Node.js event loop at 100% CPU for the whole duration. In production environments such as upload validators, image proxies or link unfurl services, a small number of concurrent requests is enough to deny service.\n\n## Root Cause Analysis\n\nTwo independent problems.\n\n1. **Absence of input size cap in the sync path.** `lib/parse_sync/svg.js` copied the entire buffer into a string and matched against it. There was no size limit at all, so cost scaled with the size of the attacker-supplied buffer.\n\n2. **Repeated rescanning in the stream path.** `lib/parse_stream/svg.js` did cap accumulated data at 64 KB, but called `parseSvg(str)` on the whole accumulated string on *every* chunk, giving `O(chunks \u00d7 N\u00b2)`. The cap does not help here: the more chunks the input is split into, the more times the quadratic scan is repeated.\n\n   Chunk size is influenced by the sender. `highWaterMark` (16 KB) is a buffering threshold, not a lower bound \u2014 a socket read returns whatever has arrived. A server that writes one byte at a time produces one-byte chunks; this was confirmed against the real `needle` pipeline with default options.\n\nThe original report identified (1) only, and stated that the 64 KB cap mitigates the streaming path. It does not.\n\n## Proof of Concept (PoC)\n\nSynchronous:\n\n```js\nconst probe = require(\u0027probe-image-size\u0027)\n\n// ~200 KB of \u0027\u003ca\u0027 \u2014 contains \u0027\u003c\u0027 but never \u0027\u003e\u0027\nprobe.sync(Buffer.from(\u0027\u003ca\u0027.repeat(100000), \u0027latin1\u0027))\n```\n\nStreaming \u2014 the same payload split into chunks, slower per byte than the synchronous form:\n\n```js\nconst { Readable } = require(\u0027stream\u0027)\nconst probe = require(\u0027probe-image-size\u0027)\n\nconst payload = Buffer.from(\u0027\u003ca\u0027.repeat(32768), \u0027latin1\u0027)\nconst chunks = []\nfor (let i = 0; i \u003c payload.length; i += 4096) chunks.push(payload.subarray(i, i + 4096))\n\nawait probe(Readable.from(chunks))\n```\n\nMeasurements on the maintainer\u0027s machine:\n\n| path | input | time |\n| --- | --- | --- |\n| `probe.sync()` | 25 KB | 0.9 s |\n| `probe.sync()` | 50 KB | 5.5 s |\n| `probe.sync()` | 100 KB | 18 s |\n| `probe.sync()` | 200 KB | 54 s |\n| `probe(stream)` | 64 KB, 1 chunk | 1.6 s |\n| `probe(stream)` | 64 KB, 4 chunks | 2.9 s |\n| `probe(stream)` | 64 KB, 16 chunks | 9.6 s |",
  "id": "GHSA-gjj5-9665-rwrc",
  "modified": "2026-10-02T23:18:02Z",
  "published": "2026-10-02T23:18:02Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/probe-image-size/security/advisories/GHSA-gjj5-9665-rwrc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-104861"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/probe-image-size/commit/60cc96ac0b671e79e328213d0a8e831312b09e84"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/probe-image-size/commit/9b74656d6f973cc59ea2ab1375c0d88390a402ad"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/probe-image-size/commit/c032aefabdecf5cb50548ab9ba175db56353078f"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/nodeca/probe-image-size"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nodeca/probe-image-size/releases/tag/7.4.0"
    }
  ],
  "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": "probe-image-size: Quadratic-time Denial of Service in the SVG Parser"
}

CVE-2026-104861 (GCVE-0-2026-104861)

Vulnerability from cvelistv5 – Published: 2026-10-02 17:56 – Updated: 2026-10-02 18:20

Title

probe-image-size: Quadratic-time Denial of Service in the SVG Parser

Summary

probe-image-size gets image dimensions without downloading the entire file. Prior to 7.4.0, lib/parse_sync/svg.js and lib/parse_stream/svg.js use the searching regular expression /<[-_.:a-zA-Z0-9][^>]*>/, which repeatedly scans to the end of input when attacker-controlled data contains many less-than characters without a closing greater-than character. The synchronous parser converts and scans the full supplied buffer without an input cap, while the streaming parser reparses the complete accumulated SVG prefix for every received chunk. The probe.sync(), probe(stream), and probe(url) entry points can therefore block the Node.js event loop at full CPU, and attacker-controlled chunking can amplify the streaming cost. This issue is fixed in version 7.4.0.

Severity

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-02 18:19 UTC

CWE

CWE-400 - Uncontrolled Resource Consumption
CWE-1333 - Inefficient Regular Expression Complexity

Assigner

GitHub_M mitre root Scorecard

References

5 references

URL	Tags
https://github.com/nodeca/probe-image-size/securi…	x_refsource_CONFIRM
https://github.com/nodeca/probe-image-size/commit…	x_refsource_MISC
https://github.com/nodeca/probe-image-size/commit…	x_refsource_MISC
https://github.com/nodeca/probe-image-size/commit…	x_refsource_MISC
https://github.com/nodeca/probe-image-size/releas…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
nodeca	probe-image-size	Affected: < 7.4.0

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-104861",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-02T18:19:55.305774Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-10-02T18:20:12.054Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/nodeca/probe-image-size/security/advisories/GHSA-gjj5-9665-rwrc"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "probe-image-size",
          "vendor": "nodeca",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 7.4.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "probe-image-size gets image dimensions without downloading the entire file. Prior to 7.4.0, lib/parse_sync/svg.js and lib/parse_stream/svg.js use the searching regular expression /\u003c[-_.:a-zA-Z0-9][^\u003e]*\u003e/, which repeatedly scans to the end of input when attacker-controlled data contains many less-than characters without a closing greater-than character. The synchronous parser converts and scans the full supplied buffer without an input cap, while the streaming parser reparses the complete accumulated SVG prefix for every received chunk. The probe.sync(), probe(stream), and probe(url) entry points can therefore block the Node.js event loop at full CPU, and attacker-controlled chunking can amplify the streaming cost. This issue is fixed in version 7.4.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
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          }
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      "problemTypes": [
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          "descriptions": [
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              "cweId": "CWE-400",
              "description": "CWE-400: Uncontrolled Resource Consumption",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-1333",
              "description": "CWE-1333: Inefficient Regular Expression Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-02T17:56:15.515Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
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          "tags": [
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          "url": "https://github.com/nodeca/probe-image-size/security/advisories/GHSA-gjj5-9665-rwrc"
        },
        {
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          "tags": [
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          ],
          "url": "https://github.com/nodeca/probe-image-size/commit/60cc96ac0b671e79e328213d0a8e831312b09e84"
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        {
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          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/nodeca/probe-image-size/commit/9b74656d6f973cc59ea2ab1375c0d88390a402ad"
        },
        {
          "name": "https://github.com/nodeca/probe-image-size/commit/c032aefabdecf5cb50548ab9ba175db56353078f",
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          "url": "https://github.com/nodeca/probe-image-size/commit/c032aefabdecf5cb50548ab9ba175db56353078f"
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        {
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          "url": "https://github.com/nodeca/probe-image-size/releases/tag/7.4.0"
        }
      ],
      "source": {
        "advisory": "GHSA-gjj5-9665-rwrc",
        "discovery": "UNKNOWN"
      },
      "title": "probe-image-size: Quadratic-time Denial of Service in the SVG Parser"
    }
  },
  "cveMetadata": {
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    "cveId": "CVE-2026-104861",
    "datePublished": "2026-10-02T17:56:15.515Z",
    "dateReserved": "2026-10-02T14:38:43.244Z",
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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