SB2026090825 - Path traversal in Fastify-http-proxy

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Main Vulnerability Database SB2026090825

SB2026090825 - Path traversal in Fastify-http-proxy

Published: September 8, 2026

Security Bulletin ID SB2026090825
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Information disclosure

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Path traversal (CVE-ID: CVE-2026-85124)

CWE-ID: CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to access restricted upstream paths.

The vulnerability exists due to improper limitation of a pathname to a restricted directory in the plain HTTP request path of @fastify/http-proxy when processing requests containing backslash dot-segments. A remote attacker can send a specially crafted request to access restricted upstream paths.

Only applications relying on prefix and rewritePrefix to isolate upstream URL space are affected.


Remediation

Install update from vendor's website.

References