What is CVE-2022-31152?

CVE-2022-31152 is a medium-severity vulnerability in Matrix Synapse, classified under CWE-703. CVSS score: 6.4/10. Published 2022-09-02.

How severe is CVE-2022-31152?

Medium severity. CVSS v3 base score is 6.4 out of 10.

Vulnerability in Matrix Synapse

CVE-2022-31152

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.

Published 2022-09-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H.

EPSS exploit prediction

EPSS: 0.012 (66.4th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.012 · change: +0.000

Affected products

Matrix Synapse
Matrix-Org Synapse — versions < 1.62.0

Weakness classification (CWE)

References

github.com/matrix-org/synapse/security/advisories/GHSA-jhjh-776m-4765 (Third Party Advisory, Mitigation, Issue Tracking)
github.com/matrix-org/synapse/pull/13087 (Patch, Third Party Advisory, Issue Tracking)
github.com/matrix-org/synapse/pull/13088 (Patch, Third Party Advisory, Issue Tracking)
github.com/matrix-org/synapse/releases/tag/v1.62.0 (Third Party Advisory, Release Notes)

Frequently asked questions

What is CVE-2022-31152?: CVE-2022-31152 is a medium-severity vulnerability in Matrix Synapse, classified under CWE-703. CVSS score: 6.4/10. Published 2022-09-02.
How severe is CVE-2022-31152?: Medium severity. CVSS v3 base score is 6.4 out of 10.