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. A potential workaround might be to prevent users from making custom push rules, by blocking such requests at a reverse-proxy.
History

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2021-05-11T15:05:12

Updated: 2024-08-03T22:11:05.476Z

Reserved: 2021-03-30T00:00:00

Link: CVE-2021-29471

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-05-11T15:15:08.507

Modified: 2023-11-07T03:32:37.617

Link: CVE-2021-29471

cve-icon Redhat

No data.