In short
- CVE-2022-39374 is a MEDIUM (CVSS 6.5) vulnerability affecting matrix-synapse, synapse (matrix).
- Chance of exploitation in the next 30 days (EPSS): 0.94%, higher than 61.0% of all vulnerabilities.
- Fix: update to 1.68.0, 1.68.0rc1 or later.
| Package | Affected versions | Patched versions |
|---|
| matrix-synapse PyPI | ≥ 1.62.0, < 1.68.0≥ 1.62.0, < 1.68.0rc1
| 1.68.01.68.0rc1
|
| synapse | ≥ 1.62.0, < 1.68.0
| 1.68.0
|
Description
Impact
If Synapse and a malicious homeserver are both joined to the same room, the malicious homeserver can trick Synapse into accepting previously rejected events into its view of the current state of that room. This can be exploited in a way that causes all further messages and state changes sent in that room from the vulnerable homeserver to be rejected.
Synapse homeservers are affected by this issue if and only if they are joined to rooms which members of untrusted homeservers are joined or invited to.
- Synapse homeservers in rooms available over public federation are affected.
- Synapse homeservers with federation disabled are not affected.
- Synapse homeservers in a closed federation containing only trusted servers are not affected.
- Synapse homeservers which are only joined to rooms with federation disabled1 are not affected.
Patches
Administrators of homeservers with federation enabled are advised to upgrade to 1.68.0 or higher.
Workarounds
- Federation can be disabled by setting
federation_domain_whitelist to an empty list ([]). from the vulnerable homeserver to be rejected. This issue has been patched in version 1.68.0
References
For more information
If you have any questions or comments about this advisory, e-mail us at [email protected].
NVD description
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. If Synapse and a malicious homeserver are both joined to the same room, the malicious homeserver can trick Synapse into accepting previously rejected events into its view of the current state of that room. This can be exploited in a way that causes all further messages and state changes sent in that room from the vulnerable homeserver to be rejected. This issue has been patched in version 1.68.0
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