FKIE_CVE-2026-76169
Vulnerability from fkie_nvd - Published: 2026-09-04 10:17 - Updated: 2026-09-15 20:07
Severity
Summary
fastify versions >= 4.0.0 and before 5.12.2 can route a malformed URL sent under one plugin prefix to the custom not-found handler of a different sibling plugin, and invoke it without the preHandler hook declared for that handler. The internal not-found router for encapsulated handlers dispatches malformed paths through a single shared handler pointer before URL decoding, ignoring the prefix and skipping the selected handler's normal lifecycle. An unauthenticated attacker can therefore reach an authentication-protected private fallback through an unrelated public prefix and read its full response, bypassing the authentication hook and breaking prefix encapsulation. Users should upgrade to fastify 5.12.2 or later.
References
| URL | Tags | ||
|---|---|---|---|
| ce714d77-add3-4f53-aff5-83d477b104bb | https://cna.openjsf.org/security-advisories.html | Third Party Advisory | |
| ce714d77-add3-4f53-aff5-83d477b104bb | https://github.com/fastify/fastify/security/advisories/GHSA-p68q-wchp-6fh7 | Mitigation, Vendor Advisory |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"packageURL": "pkg:npm/fastify",
"product": "fastify",
"vendor": "fastify",
"versions": [
{
"lessThan": "5.12.2",
"status": "affected",
"version": "4.0.0",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.12.2",
"versionType": "semver"
}
]
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:fastify:fastify:*:*:*:*:*:node.js:*:*",
"matchCriteriaId": "65C76641-6C57-4380-9FCA-50034F2ACDAC",
"versionEndExcluding": "5.12.2",
"versionStartIncluding": "4.0.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "fastify versions \u003e= 4.0.0 and before 5.12.2 can route a malformed URL sent under one plugin prefix to the custom not-found handler of a different sibling plugin, and invoke it without the preHandler hook declared for that handler. The internal not-found router for encapsulated handlers dispatches malformed paths through a single shared handler pointer before URL decoding, ignoring the prefix and skipping the selected handler\u0027s normal lifecycle. An unauthenticated attacker can therefore reach an authentication-protected private fallback through an unrelated public prefix and read its full response, bypassing the authentication hook and breaking prefix encapsulation. Users should upgrade to fastify 5.12.2 or later."
}
],
"id": "CVE-2026-76169",
"lastModified": "2026-09-15T20:07:46.700",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.5,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "NONE",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6,
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-76169",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-04T16:18:32.577097Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-04T10:17:12.020",
"references": [
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Third Party Advisory"
],
"url": "https://cna.openjsf.org/security-advisories.html"
},
{
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"tags": [
"Mitigation",
"Vendor Advisory"
],
"url": "https://github.com/fastify/fastify/security/advisories/GHSA-p68q-wchp-6fh7"
}
],
"sourceIdentifier": "ce714d77-add3-4f53-aff5-83d477b104bb",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-288"
}
],
"source": "ce714d77-add3-4f53-aff5-83d477b104bb",
"type": "Secondary"
}
]
}
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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