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GHSA-jhjh-776m-4765
No affected components available
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 can be disabled by setting
federation_domain_whitelistto an empty list ([]).
References
- https://github.com/matrix-org/synapse/pull/13087
- https://github.com/matrix-org/synapse/pull/13088
For more information
If you have any questions or comments about this advisory, e-mail us at security@matrix.org.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the availability of the system.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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