CVE-2026-18427

Description

@fastify/static before version 10.1.3 contains an incomplete fix for a previous route guard bypass. The static file handler rejected only parent directory segments, but it did not canonicalize dot segments, duplicate slashes, encoded dots, or backslashes before route matching and before delegating to the send layer. As a result, an unauthenticated attacker could request a file protected by a route based guard using a non canonical path form that misses the guarded route yet resolves back onto the protected file, disclosing its contents. Applications that protect a subtree of the static root with a route based guard are affected, while applications relying on the allowedPath option are not. This is fixed in @fastify/static 10.1.3, which canonicalizes the pathname, including rejecting backslashes, on the path used for routing and serving.

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Produits concernés

• @fastify/static
• Fastify fastify-static

Scores CVSS

Faiblesses (CWE)

• CWE-22
• CWE-436

Références

• https://cna.openjsf.org/security-advisories.html Third Party Advisory
• https://github.com/fastify/fastify-static/security/advisories/GHSA-423g-23ch-w7c6 MitigationVendor Advisory

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories