CVE-2023-43796 Information

Description

Synapse is an open-source Matrix homeserver Prior to versions 1.95.1 and 1.96.0rc1 cached device information of remote users can be queried from Synapse. This can be used to enumerate the remote users known to a homeserver. System administrators are encouraged to upgrade to Synapse 1.95.1 or 1.96.0rc1 to receive a patch. As a workaround the federation_domain_whitelist can be used to limit federation traffic with a homeserver.

Reference

https://github.com/matrix-org/synapse/security/advisories/GHSA-mp92-3jfm-3575 https://github.com/matrix-org/synapse/commit/daec55e1fe120c564240c5386e77941372bf458f