CVE-2026-6414

@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 v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://cna.openjsf.org/security-advisories.html	Third Party Advisory
https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92	Vendor Advisory
https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p	Not Applicable
https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr	Not Applicable

Configurations

Configuration 1 (hide)

cpe:2.3:a:fastify:fastify-static:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-16 13:16

Updated : 2026-06-17 11:00

NVD link : CVE-2026-6414

Mitre link : CVE-2026-6414

CVE.ORG link : CVE-2026-6414

JSON object : View

Products Affected

fastify

fastify-static

CWE

CWE-177

Improper Handling of URL Encoding (Hex Encoding)

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