Impact
The Matrix specification specifies a list of event 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 v1.61, 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.
Patches
Administrators of homeservers with federation enabled are advised to upgrade to v1.62.0 or higher.
Workarounds
References
For more information
If you have any questions or comments about this advisory, e-mail us at [email protected].
Impact
The Matrix specification specifies a list of event 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 v1.61, 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.
Patches
Administrators of homeservers with federation enabled are advised to upgrade to v1.62.0 or higher.
Workarounds
federation_domain_whitelistto an empty list ([]).References
For more information
If you have any questions or comments about this advisory, e-mail us at [email protected].