CVE-2022-31152: Synapse vulnerable to denial of service (DoS) due to incorrect application of event authorization rules
First published: Wed Aug 31 2022(Updated: )
### Impact The Matrix specification specifies a list of [event authorization rules](https://spec.matrix.org/v1.3/rooms/v10/#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_whitelist`](https://matrix-org.github.io/synapse/latest/usage/configuration/config_documentation.html#federation_domain_whitelist) to 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](mailto:security@matrix.org).
Credit: security-advisories@github.com security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Matrix Synapse | <1.62.0 | |
| pip/matrix-synapse | <1.62.0rc1 | 1.62.0rc1 |
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Reference Links
- https://github.com/matrix-org/synapse/pull/13087
- https://github.com/matrix-org/synapse/pull/13088
- https://github.com/matrix-org/synapse/releases/tag/v1.62.0
- https://github.com/matrix-org/synapse/security/advisories/GHSA-jhjh-776m-4765
- https://nvd.nist.gov/vuln/detail/CVE-2022-31152
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2022-262.yaml
- https://github.com/matrix-org/synapse/commit/d4b1c0d800eaa83c4d56a9cf17881ad362b9194b
- https://github.com/matrix-org/synapse/commit/e16ea87d0f8c4c30cad36f85488eb1f647e640b0
- https://github.com/advisories/GHSA-jhjh-776m-4765 (Advisory)
Frequently Asked Questions
What is CVE-2022-31152?
CVE-2022-31152 is a vulnerability in Synapse, an open-source Matrix homeserver, which allows attackers to bypass event authorization rules.
What is the severity of CVE-2022-31152?
The severity of CVE-2022-31152 is high, with a severity value of 7.5.
How does CVE-2022-31152 affect Matrix Synapse?
CVE-2022-31152 affects Matrix Synapse versions up to and excluding 1.62.0.
How can I fix CVE-2022-31152?
To fix CVE-2022-31152, it is recommended to update Matrix Synapse to version 1.62.0 or later.
What are the Common Weakness Enumerations (CWEs) associated with CVE-2022-31152?
CVE-2022-31152 is associated with CWE-755 (Improper Handling of Exceptional Conditions) and CWE-703 (Improper Check or Handling of Exceptional Conditions).
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