First published: Fri Sep 02 2022(Updated: )
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. The Matrix specification specifies a list of [event authorization rules](https://spec.matrix.org/v1.2/rooms/v9/#authorization-rules) which must be checked when determining if an event should be accepted into a room. In versions of Synapse up to and including version 1.61.0, some of these rules are not correctly applied. An attacker could craft events which would be accepted by Synapse but not a spec-conformant server, potentially causing divergence in the room state between servers. Administrators of homeservers with federation enabled are advised to upgrade to version 1.62.0 or higher. Federation can be disabled by setting [`federation_domain_whitelist`](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#federation_domain_whitelist) to an empty list (`[]`) as a workaround.
Credit: security-advisories@github.com
Affected Software | Affected Version | How to fix |
---|---|---|
Matrix Synapse | <1.62.0 |
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CVE-2022-31152 is a vulnerability in Synapse, an open-source Matrix homeserver, which allows attackers to bypass event authorization rules.
The severity of CVE-2022-31152 is high, with a severity value of 7.5.
CVE-2022-31152 affects Matrix Synapse versions up to and excluding 1.62.0.
To fix CVE-2022-31152, it is recommended to update Matrix Synapse to version 1.62.0 or later.
CVE-2022-31152 is associated with CWE-755 (Improper Handling of Exceptional Conditions) and CWE-703 (Improper Check or Handling of Exceptional Conditions).