Vulnerability CVE-2020-26891: Information
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.
Severity: MEDIUM (6.1) Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Fixed packages
Package name | Branch | Fixed in version | Version from repository | Errata ID | Task # | State |
|---|---|---|---|---|---|---|
| matrix-synapse | sisyphus | 1.21.0-alt1 | 1.104.0-alt1 | ALT-PU-2020-3036-1 | 259805 | Fixed |
| matrix-synapse | p10 | 1.21.0-alt1 | 1.38.0-alt1 | ALT-PU-2020-3036-1 | 259805 | Fixed |
| matrix-synapse | c10f1 | 1.21.0-alt1 | 1.38.0-alt1 | ALT-PU-2020-3036-1 | 259805 | Fixed |
References to Advisories, Solutions, and Tools
Hyperlink | Resource |
|---|---|
| https://matrix.org/blog/2020/10/15/synapse-1-21-2-released-and-security-advisory |
|
| 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 |
|