CVE-2026-6414
This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static.
Does this matter?
Lower severity and a low EPSS score (0.41%). Track it; it rarely justifies an emergency change on its own.
Description
@fastify/static versions 8.0.0 through 9.1.0 decode percent-encoded path separators (%2F) before filesystem resolution, while Fastify's router treats them as literal characters. This mismatch allows attackers to bypass route-based middleware or guards that protect files served by @fastify/static. For example, a route guard on a protected path can be circumvented by encoding the path separator in the URL. Upgrade to @fastify/static 9.1.1 to fix this issue. There are no workarounds.
- CVSS 3.1
- 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.41% probability · 35th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-177
- Affected
- fastify/fastify-static
- Source
- ce714d77-add3-4f53-aff5-83d477b104bb
References
- https://cna.openjsf.org/security-advisories.htmlThird Party Advisory
- https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92Vendor Advisory
- https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69pNot Applicable
- https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwrNot Applicable
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.