CVE-2023-32323
A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y.
Does this matter?
Lower severity and a low EPSS score (0.98%). Track it; it rarely justifies an emergency change on its own.
Description
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. A malicious user on a Synapse homeserver X with permission to create certain state events can disable outbound federation from X to an arbitrary homeserver Y. Synapse instances with federation disabled are not affected. In versions of Synapse up to and including 1.73, Synapse did not limit the size of `invite_room_state`, meaning that it was possible to create an arbitrarily large invite event. Synapse 1.74 refuses to create oversized `invite_room_state` fields. Server operators should upgrade to Synapse 1.74 or newer urgently.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 0.98% probability · 60th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- matrix/synapse
- Source
- security-advisories@github.com
References
- https://github.com/matrix-org/synapse/issues/14492Exploit, Issue Tracking
- https://github.com/matrix-org/synapse/pull/14642Patch
- https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvrMitigation, Vendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/
- https://github.com/matrix-org/synapse/issues/14492Exploit, Issue Tracking
- https://github.com/matrix-org/synapse/pull/14642Patch
- https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvrMitigation, Vendor Advisory
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.