CVE-2021-29471 log

Severity Medium
Remote Yes
Type Denial of service
In Synapse before version 1.33.2 "Push rules" can specify conditions under which they will match, including `event_match`, which matches event content against a pattern including wildcards. Certain patterns can cause very poor performance in the matching engine, leading to a denial-of-service when processing moderate length events. The issue is patched in version 1.33.2. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.
Group Package Affected Fixed Severity Status Ticket
AVG-1943 matrix-synapse 1.29.0-1 1.33.2-1 Medium Fixed FS#70801
Date Advisory Group Package Severity Type
25 May 2021 ASA-202105-19 AVG-1943 matrix-synapse Medium denial of service