CVE-2026-6414

Updated on 16 Apr 2026

Severity

5.9 Medium severity

Details

CVSS score
5.9
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Overview

About vulnerability

@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.

Details

Affected product:
Fastify
Affected packages:
@fastify/static @ 8.3.0 (+2 more)