CVE-2022-31152
Denial of service due to incorrect application of event authorization rules
Description
Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. The Matrix specification specifies a list of [event authorization rules](https://spec.matrix.org/v1.2/rooms/v9/#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 version 1.61.0, 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. Administrators of homeservers with federation enabled are advised to upgrade to version 1.62.0 or higher. Federation can be disabled by setting [`federation_domain_whitelist`](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#federation_domain_whitelist) to an empty list (`[]`) as a workaround.
How to fix CVE-2022-31152
To remediate CVE-2022-31152, upgrade the affected package to a fixed version below.
- —upgrade to 1.63.0-1 or later
- —upgrade to 1.62.0rc1 or later
- —upgrade to 1.62.0 or later
Is CVE-2022-31152 being exploited?
Low — EPSS is 0.7%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.63.0-1
- from 0, < 1.62.0rc1
- from 0, < 1.62.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |