CVSS 3.0
7.5 highCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NCVE-2018-12291
High (7.5) in matrix synapse. EPSS 1.8% chance of exploitation in the next 30 days. Fixed in matrix-synapse 0.31.1.
The on_get_missing_events function in handlers/federation.py in Matrix Synapse before 0.31.1 has a security bug in the get_missing_events federation API where event visibility rules were not applied correctly.
Severity
- EPSS
- 1.8% chance of exploitation in the next 30 days; higher than 78% of CVEs (scores of 2026-10-31)
- Published
- Modified
- Record from
- the NVD, synced
Affected
- matrix:synapse
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-v8wm-g9f2-xjv4 | PyPI | matrix-synapse | <0.31.1 | 0.31.1 |
| PYSEC-2026-664 | PyPI | matrix-synapse | <0.31.1 | 0.31.1 |