AIKIDO-2026-805288
@fastify/http-proxy is vulnerable to Path Traversal
75
High Risk
This Affects:
@fastify/http-proxyTL;DR
The plain HTTP request handler does not validate proxied destinations against the rewritePrefix boundary the way the WebSocket path does. Backslash-based dot-segments such as \..\ bypass @fastify/reply-from's forward-slash-only traversal guard, so new URL() collapses them and escapes the prefix/rewritePrefix boundary to reach upstream paths that were meant to stay hidden. The fix applies the same destination validation to HTTP request paths that WebSocket destinations already receive.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and use prefix and rewritePrefix to isolate part of an upstream URL space behind the HTTP proxy.
Background info
@fastify/http-proxy is vulnerable to Path Traversal in versions 7.0.0 - 11.6.1.
How to fix this
Upgrade the @fastify/http-proxy library to the patch version.
Are You Affected?
Connect your repositories to instantly see whether vulnerable or malicious packages exist in your codebase.
Free. No credit card required.
I consent to receiving marketing communications based on Aikido’s Privacy Policy.
SOC 2Compliant
ISO 27001CompliantISO 42001Compliant
FedRAMPImplementing© All Intel data is openly available and commercially licensed.