CVE-2020-26891

EPSS 1.9%

Vexday Risk Score

3Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS —EPSS 1.9%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

19 Oct 2020Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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.

Affected products

n/a · n/a

Want to know if your infrastructure is exposed to this?

Talk to TrueHacking →

References

https://github.com/matrix-org/synapse/pull/8444 https://github.com/matrix-org/synapse/releases/tag/v1.21.2 https://github.com/matrix-org/synapse/security/advisories/GHSA-3x8c-fmpc-5rmq https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory