CVE-2022-31152
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.18%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.18% probability · 67th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-703, CWE-755
- Affected
- matrix/synapse
- Source
- security-advisories@github.com
EPSS 1.2% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/matrix-org/synapse/pull/13087Issue Tracking, Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/13088Issue Tracking, Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.62.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-jhjh-776m-4765Issue Tracking, Mitigation, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/13087Issue Tracking, Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/pull/13088Issue Tracking, Patch, Third Party Advisory
- https://github.com/matrix-org/synapse/releases/tag/v1.62.0Release Notes, Third Party Advisory
- https://github.com/matrix-org/synapse/security/advisories/GHSA-jhjh-776m-4765Issue Tracking, Mitigation, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.