Synapse allows a a malformed invite to break the invitee's `/sync`
Priority MEDIUM 44CWE-20Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
Synapse is an open-source Matrix homeserver. Synapse versions before 1.120.1 fail to properly validate invites received over federation. This vulnerability allows a malicious server to send a specially crafted invite that disrupts the invited user's /sync functionality. Synapse 1.120.1 rejects such invalid invites received over federation and restores the ability to sync for affected users.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0057 47th 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
- Yes
- 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 | before 1.120.1 | 1.120.1 | Patch available | CNA |
| — | matrix-synapse (PyPI) | before 1.120.1 | 1.120.1 | Patch available | GHSA-f3r3-h2mq-hx2h |
- synapse Vendorelement-hq Affected before 1.120.1 Fixed in 1.120.1 Patch available CNA
- matrix-synapse (PyPI) Vendor— Affected before 1.120.1 Fixed in 1.120.1 Patch available GHSA-f3r3-h2mq-hx2h
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* | before 1.120.1 | Vulnerable | matrix-org |
- cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:* Versions before 1.120.1 Vulnerable ·matrix-org
Remediation
- Fix · CNA synapse (element-hq) Fixed in 1.120.1
- Fix · GHSA-f3r3-h2mq-hx2h matrix-synapse (PyPI) Fixed in 1.120.1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2024-52815
- 2026-10-03 Alias added: GHSA-f3r3-h2mq-hx2h
References
More element-hq vulnerabilities
- 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
- TI-2026-35452 Element Call reports full URLs of visited pages to analytics server CVSS 4.0HIGH 8.6
Sources
- CVE-2024-52815 · CVE Program
- CVE-2024-52815 · NVD
- FIRST EPSS
- GHSA-f3r3-h2mq-hx2h · GitHub Advisory Database · CC BY 4.0
- CVE-2024-52815 · 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