CVE-2023-32323

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.

• CWE-20
• CWE-20

• 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/

Published

May 26, 2023

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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