Synapse Matrix has a partial room state leak via Sliding Sync
Priority LOW 20CWE-497Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-497.
Summary
Synapse is an open-source Matrix homeserver. The Sliding Sync feature on Synapse versions between 1.113.0rc1 and 1.120.0 can leak partial room state changes to users no longer in a room. Non-state events, like messages, are unaffected. This vulnerability is fixed in 1.120.1.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00442 38th percentileScored 2026-11-07
Fix Fixed synapse (element-hq): 1.120.1matrix-synapse (PyPI): 1.120.1
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 |
|---|---|---|---|---|---|
| element-hq | synapse | 1.113.0rc1 to before 1.120.1 | 1.120.1 | Patch available | CNA |
| — | matrix-synapse (PyPI) | 1.113.0rc1 to before 1.120.1 | 1.120.1 | Patch available | GHSA-56w4-5538-8v8h |
- synapse Vendorelement-hq Affected 1.113.0rc1 to before 1.120.1 Fixed in 1.120.1 Patch available CNA
- matrix-synapse (PyPI) Vendor— Affected 1.113.0rc1 to before 1.120.1 Fixed in 1.120.1 Patch available GHSA-56w4-5538-8v8h
Remediation
- Fix · CNA synapse (element-hq) Fixed in 1.120.1
- Fix · GHSA-56w4-5538-8v8h matrix-synapse (PyPI) Fixed in 1.120.1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2024-53867
- 2026-10-03 Alias added: GHSA-56w4-5538-8v8h
References
More element-hq vulnerabilities
- TI-2024-35327 Synapse allows a a malformed invite to break the invitee's `/sync` CVSS 4.0HIGH 8.7
- 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-2022-07650 Remote program execution with user interaction CVSS 3.1HIGH 8.8
- TI-2026-19372 ESS Community Helm Chart has a weak server key generation method CVSS 4.0CRITICAL 9.2
- TI-2024-24814 Synapse denial of service through media disk space consumption CVSS 3.1HIGH 7.5
Sources
- CVE-2024-53867 · CVE Program
- CVE-2024-53867 · NVD
- FIRST EPSS
- GHSA-56w4-5538-8v8h · GitHub Advisory Database · CC BY 4.0
- CVE-2024-53867 · 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