GHSA-CRVJ-82CR-HJCX
Vulnerability from github – Published: 2026-09-08 21:22 – Updated: 2026-09-08 21:22
VLAI
Summary
Hono: Query parser reads parameters after the URL fragment, causing cache-key and proxy interpretation differentials
Details
Summary
Hono's query parsing does not stop at the URL fragment: a ? appearing after a # is treated as the start of a query string. As a result, the application can read request parameters that no other component involved in handling the request can see.
Details
A fragment is never part of the query, and every standard URL consumer — browsers, new URL(), reverse proxies — ignores everything from the first # onward. Hono's routing followed that rule; its query helpers did not.
For one and the same request, this produces an interpretation differential:
- A component in front of the application that inspects the query string — filtering rules, parameter allow/deny lists, access logging — observes no parameters, while the application reads and acts on them.
- The cache middleware removed the fragment when building its cache key, so a response influenced by parameters carried inside the fragment could be stored under a key that did not reflect them and later returned to other users.
The same divergence reaches request validation and any middleware that reads query parameters.
This requires a request target containing a literal # to reach the application. Deployments on runtimes that normalise such a target — including Cloudflare Workers — are not affected, and neither are those behind an intermediary that strips the fragment.
Impact
An attacker can cause the application to act on parameters that components in front of it never observe.
This may lead to:
- filtering rules, allow/deny lists, and audit logging being blind to parameters the application still processes
- a cached response being stored under a key that does not reflect the parameters used to produce it, and served to other users
- stored cross-site scripting, where such a parameter is reflected into a cached HTML response without escaping
This issue affects applications that read query parameters and run on a runtime that passes a literal # through to the request URL.
Severity
5.9 (Medium)
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "hono"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.13.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-84363"
],
"database_specific": {
"cwe_ids": [
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-08T21:22:50Z",
"nvd_published_at": "2026-09-01T21:18:47Z",
"severity": "MODERATE"
},
"details": "### Summary\n\nHono\u0027s query parsing does not stop at the URL fragment: a `?` appearing after a `#` is treated as the start of a query string. As a result, the application can read request parameters that no other component involved in handling the request can see.\n\n### Details\n\nA fragment is never part of the query, and every standard URL consumer \u2014 browsers, `new URL()`, reverse proxies \u2014 ignores everything from the first `#` onward. Hono\u0027s routing followed that rule; its query helpers did not.\n\nFor one and the same request, this produces an interpretation differential:\n\n- A component in front of the application that inspects the query string \u2014 filtering rules, parameter allow/deny lists, access logging \u2014 observes no parameters, while the application reads and acts on them.\n- The cache middleware removed the fragment when building its cache key, so a response influenced by parameters carried inside the fragment could be stored under a key that did not reflect them and later returned to other users.\n\nThe same divergence reaches request validation and any middleware that reads query parameters.\n\nThis requires a request target containing a literal `#` to reach the application. Deployments on runtimes that normalise such a target \u2014 including Cloudflare Workers \u2014 are not affected, and neither are those behind an intermediary that strips the fragment.\n\n### Impact\n\nAn attacker can cause the application to act on parameters that components in front of it never observe.\n\nThis may lead to:\n\n- filtering rules, allow/deny lists, and audit logging being blind to parameters the application still processes\n- a cached response being stored under a key that does not reflect the parameters used to produce it, and served to other users\n- stored cross-site scripting, where such a parameter is reflected into a cached HTML response without escaping\n\nThis issue affects applications that read query parameters and run on a runtime that passes a literal `#` through to the request URL.",
"id": "GHSA-crvj-82cr-hjcx",
"modified": "2026-09-08T21:22:50Z",
"published": "2026-09-08T21:22:50Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/honojs/hono/security/advisories/GHSA-crvj-82cr-hjcx"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84363"
},
{
"type": "WEB",
"url": "https://github.com/honojs/hono/commit/9c28d724c5a7fb086ebaa812fdc1ad6e957c63bc"
},
{
"type": "PACKAGE",
"url": "https://github.com/honojs/hono"
},
{
"type": "WEB",
"url": "https://github.com/honojs/hono/releases/tag/v4.13.5"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Hono: Query parser reads parameters after the URL fragment, causing cache-key and proxy interpretation differentials"
}
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Sightings
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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.
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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.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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