CVE-2021-29471 - log back

CVE-2021-29471 edited at 11 May 2021 15:53:04
Severity
- Unknown
+ Medium
Remote
- Unknown
+ Remote
Type
- Unknown
+ Denial of service
Description
+ 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.
References
+ https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85
+ https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c
Notes
CVE-2021-29471 created at 11 May 2021 15:51:58