cbcvebase.
CVE-2020-26891
published 2020-10-19

CVE-2020-26891: 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…

medium6.1CVSS 3.1
AVNACLPRNUIRSCCLILAN
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.

Affected

2 ranges
VendorProductVersion rangeFixed in
debianmatrix-synapse< matrix-synapse 1.21.1-1 (forky)matrix-synapse 1.21.1-1 (forky)
matrixsynapse< 1.21.01.21.0

CVSS provenance

nvdv3.16.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
osv6.1MEDIUM