Detections
Analytics
CVE-2020-26891
medium
Description
AuthRestServlet in Matrix Synapse before 1.21.0 is vulnerable to XSS due to unsafe interpolation of the session GET parameter. This allows a remote attacker to execute an XSS attack on the domain Synapse is hosted on, by supplying the victim user with a malicious URL to the /_matrix/client/r0/auth/*/fallback/web or /_matrix/client/unstable/auth/*/fallback/web Synapse endpoints.
References
https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory
https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq