CVE-2023-32323 Information

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.

Reference

https://github.com/matrix-org/synapse/security/advisories/GHSA-f3wc-3vxv-xmvr https://github.com/matrix-org/synapse/pull/14642 https://github.com/matrix-org/synapse/issues/14492