CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2025-30355
High (7.5) in matrix synapse. EPSS 1.2% chance of exploitation in the next 30 days. Fixed in matrix-synapse 1.127.1.
Synapse is an open source Matrix homeserver implementation. A malicious server can craft events which, when received, prevent Synapse version up to 1.127.0 from federating with other servers. The vulnerability has been exploited in the wild and has been fixed in Synapse v1.127.1. No known workarounds are available.
Severity
- EPSS
- 1.2% chance of exploitation in the next 30 days; higher than 68% of CVEs (scores of 2026-10-31)
- CWE
- CWE-20
- Published
- Modified
- Record from
- the NVD, synced
Affected
- matrix:synapse
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-v56r-hwv5-mxg6 | PyPI | matrix-synapse | <1.127.1 | 1.127.1 |
| PYSEC-2026-1614 | PyPI | matrix-synapse | <1.127.1 | 1.127.1 |