CVE-2021-29471

 

Published at: - 11-05-2021 05:15

Last modified: - 05-04-2022 08:06

Total changes: - 4

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

Common Vulnerability Scoring System (CVSS)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

 

Verification logic

 

Reference

• https://github.com/matrix-org/synapse/releases/tag/v1.33.2
• https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85
• https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c
• FEDORA-2021-a627cfd31e-Mailing List, Third Party Advisory

 

Keywords

NVD

 

CVE-2021-29471

 

CVE

 

Common vulnerabilities & exposures

 

CVSS

 

Common vulnerability scoring system

 

Security

 

Vulnerabilities

 

Exposures