{"schemaVersion":3,"id":"CVE-2021-29471","aliases":["GHSA-x345-32rc-8h85","PYSEC-2021-135","UBUNTU-CVE-2021-29471","DEBIAN-CVE-2021-29471"],"status":"published","duplicateOf":null,"title":null,"description":"Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. 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. 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