cvedb.io
CVE-2026-18427
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-08-06T16:16:38.350 · Last modified 2026-08-06T16:16:38.350

Summary

@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 backsl

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.