Vulnerability Report

CVE-2026-6414

Title: Fastify Static Percent-Encoded Path Traversal

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-6414.

CWE Category CWE-177
Published Date Apr 16, 2026
Modified Date Apr 23, 2026
Exploit Status Not Found
Score 5.9 CVSS v3.1
Exploit Probability (EPSS)
0.02%

Vulnerability Summary

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.

Impacted Vendors

F
fastify 1

Reference Links

https://cna.openjsf.org/security-advisories.html https://github.com/fastify/fastify-static/security/advisories/GHSA-x428-ghpx-8j92 https://github.com/fastify/middie/security/advisories/GHSA-cxrg-g7r8-w69p https://github.com/honojs/hono/security/advisories/GHSA-q5qw-h33p-qvwr
CVSS v3.1
Source Entity ce714d77-add3-4f53-aff5-83d477b104bb
Severity MEDIUM
5.9
Attack Vector
NETWORK
Complexity
HIGH
Privileges
N/A
Interaction
NONE
Confidentiality
N/A
Integrity
N/A
Availability
N/A
Scope
UNCHANGED
RAW VECTOR CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Associated Attack Patterns (CAPEC)

Total: Patterns

CVE-2026-6414 Exploits & PoCs (Proof Of Concept)

No public PoCs found in our database for this CVE.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

MODIFIED

Vulnerability data updated via NVD.

Attack Vector Matrix

Access Vector NETWORK
Complexity HIGH
Privileges N/A
Interaction NONE
CVSS Vector String CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected Stack

No specific products linked.