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CVE

CWE

Training

CVE-2026-6414

Published: Apr 16, 2026

Modified: Apr 16, 2026

PUBLISHED

CVSS v3.1

5.9

MEDIUM

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.

Vendor	Product	Versions
@fastify/static	@fastify/static	affected `8.0.0 - < 9.1.1` unaffected `9.1.1`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

References

https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p

https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr

https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92

https://cna.openjsf.org/security-advisories.html

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