VDB
DEBIAN-CVE-2020-26891
DEBIAN-CVE-2020-26891
REJECTED
CVSS 6.099999904632568 MEDIUM
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.
Risk Scores
CVSS v3.1
6.099999904632568
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Debian:14 | matrix-synapse | 0, 0.19.2+dfsg, 0.19.2+dfsg |
Timeline
- Apr 19, 2026 CVE Rejected