Synapse vulnerable to denial of service (DoS) due to incorrect application of event authorization rules
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| matrix-org | synapse | before 1.62.0 | 1.62.0 | Patch available | CNA |
| — | matrix-synapse (PyPI) | before 1.62.0rc1 | 1.62.0rc1 | Patch available | GHSA-jhjh-776m-4765 |
- synapse Vendormatrix-org Affected before 1.62.0 Fixed in 1.62.0 Patch available CNA
- matrix-synapse (PyPI) Vendor— Affected before 1.62.0rc1 Fixed in 1.62.0rc1 Patch available GHSA-jhjh-776m-4765
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | before 1.62.0 | Vulnerable | matrix-org |
- cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* Versions before 1.62.0 Vulnerable ·matrix-org
Remediation
- Fix · CNA synapse (matrix-org) Fixed in 1.62.0
- Fix · GHSA-jhjh-776m-4765 matrix-synapse (PyPI) Fixed in 1.62.0rc1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2022-31152
- 2026-10-03 Alias added: GHSA-jhjh-776m-4765
References
Patch 2
Advisory 3
Other 4
More matrix-org Synapse vulnerabilities
- TI-2023-15617 Synapse Outgoing federation to specific hosts can be disabled by sending malicious invites CVSS 3.1MEDIUM 5.0
- TI-2024-35327 Synapse allows a a malformed invite to break the invitee's `/sync` CVSS 4.0HIGH 8.7
- TI-2019-13571 Matrix Synapse before 1.5.0 mishandles signature checking on some federation APIs. CVSS 3.1CRITICAL 9.8
- TI-2024-36056 Synapse can be forced to thumbnail unexpected file formats, invoking external, potentially untrustworthy decoders CVSS 4.0HIGH 8.2
- TI-2024-35318 Synapse allows unsupported content types to lead to memory exhaustion CVSS 4.0HIGH 8.2
- TI-2018-11846 Matrix Synapse before 0.33.3.1 allows remote attackers to spoof events and possibly have… CVSS 3.0HIGH 8.8
Sources
- CVE-2022-31152 · CVE Program
- CVE-2022-31152 · NVD
- FIRST EPSS
- GHSA-jhjh-776m-4765 · GitHub Advisory Database · CC BY 4.0
- CVE-2022-31152 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences