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.
The product does not properly control the allocation and maintenance of a limited resource.
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.
| Link | Tags |
|---|---|
| https://github.com/matrix-org/synapse/security/advisories/GHSA-x345-32rc-8h85 | third party advisory patch |
| https://github.com/matrix-org/synapse/commit/03318a766cac9f8b053db2214d9c332a977d226c | third party advisory patch |
| https://github.com/matrix-org/synapse/releases/tag/v1.33.2 | third party advisory release notes |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNNAJOZNMVMXM6AS7RFFKB4QLUJ4IFEY/ | vendor advisory |