CVE-2020-26891

Name
CVE-2020-26891
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.
NVD Severity
medium
Other trackers
CVE, NVD, CERT, CVE Details, CIRCL, Arch Linux, Debian, Red Hat, Ubuntu, Gentoo, SUSE (Bugzilla), SUSE (CVE), Mageia
Mailing lists
oss-security, full-disclosure, bugtraq
Exploits
Exploit DB, Metasploit
Forges
GitHub (code, issues), Aports (code, issues)

References

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

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* synapse >= None < 1.21.0

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
synapse edge-community 1.21.1-r0 None fixed
synapse edge-community 1.20.0-r0 None possibly vulnerable
synapse 3.22-community 1.21.1-r0 None fixed
synapse 3.22-community 1.20.0-r0 None possibly vulnerable
synapse 3.21-community 1.21.1-r0 None fixed
synapse 3.20-community 1.21.1-r0 None fixed
synapse 3.19-community 1.21.1-r0 None fixed
synapse 3.18-community 1.21.1-r0 None fixed
synapse 3.17-community 1.21.1-r0 None fixed