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AIKIDO-2026-943563

matrix-synapse is vulnerable to Improper Input Validation

Improper Input ValidationGHSA-vh4c-pqh4-w3wq Published 4 days ago

31

Low Risk

This Affects:

PYTHONmatrix-synapse
0.0.1 - 1.157.1
Fixed in 1.157.2
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TL;DR

For some HTTP request paths, Synapse ignores extraneous path segments and serves a resource at an unexpected path. Because the same resource is reachable through multiple path variants, external rate-limiting keyed on the canonical path can be evaded. The Client-Server, Federation, Admin and Key Server APIs are not affected by this malleability. The fix ensures the catch-all unrecognised-request handler cannot resolve resources under inserted path segments.

Who does this affect?

You are affected if you are using a version that falls within the vulnerable range and you rely on external path-based rate limiting in front of Synapse.

Background info

matrix-synapse is vulnerable to Improper Input Validation in versions 0.0.1 - 1.157.1.

How to fix this

Upgrade the matrix-synapse library to the patch version.