Synapse Denial of service due to incorrect application of event authorization rules during state resolution
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-400.
Summary
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
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 | 1.62.0 to before 1.68.0 | 1.68.0 | Patch available | CNA |
| — | matrix-synapse (PyPI) | 1.62.0 to before 1.68.0rc1 | 1.68.0rc1 | Patch available | GHSA-p9qp-c452-f9r7 |
- synapse Vendormatrix-org Affected 1.62.0 to before 1.68.0 Fixed in 1.68.0 Patch available CNA
- matrix-synapse (PyPI) Vendor— Affected 1.62.0 to before 1.68.0rc1 Fixed in 1.68.0rc1 Patch available GHSA-p9qp-c452-f9r7
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | 1.62.0 to before 1.68.0 | Vulnerable | matrix-org |
- cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* Versions 1.62.0 to before 1.68.0 Vulnerable ·matrix-org
Remediation
- Fix · CNA synapse (matrix-org) Fixed in 1.68.0
- Fix · GHSA-p9qp-c452-f9r7 matrix-synapse (PyPI) Fixed in 1.68.0rc1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2022-39374
- 2026-10-03 Alias added: GHSA-p9qp-c452-f9r7
References
Advisory 2
Other 5
- https://lists.fedoraproject.org/archives/list/[email protected]/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD/
- https://github.com/matrix-org/synapse/commit/b73cbb82157d9666e8d667733afebc0d09ed858c
- https://github.com/matrix-org/synapse
- https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2023-66.yaml
- https://lists.fedoraproject.org/archives/list/[email protected]/message/UJIJRP5ZH6B3KGFLHCAKR2IX2Y4Z25QD
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-2022-39374 · CVE Program
- CVE-2022-39374 · NVD
- FIRST EPSS
- GHSA-p9qp-c452-f9r7 · GitHub Advisory Database · CC BY 4.0
- CVE-2022-39374 · 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