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.
SeverityMedium
CVSS6.1
Exploit probability—
ProductMatrix Synapse
PublishedOct 19, 2020
First seenOct 19, 2020
How to fix
Update
- matrix synapse1.21.0 or later
- matrix-synapse1.21.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| matrix synapse | v < 1.21.0 | 1.21.0 |
| matrix-synapsePyPI | v < 1.21.0 | 1.21.0 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.