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.
History

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cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published: 2020-10-19T16:47:17

Updated: 2024-08-04T16:03:22.630Z

Reserved: 2020-10-08T00:00:00

Link: CVE-2020-26891

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Analyzed

Published: 2020-10-19T17:15:13.220

Modified: 2020-10-26T21:30:56.057

Link: CVE-2020-26891

cve-icon Redhat

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