CVE-2026-45076
Synapse is an open source Matrix homeserver implementation. Prior to 1.152.1, in federated rooms, malicious homeservers can craft room events in such a way that prevents Synapse from providing full history to paginating clients. Clients could therefore fail to display room history. This vulnerability is fixed in 1.152.1.
- CVSS 4.0
- 5.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N - CVSS 3.1
- 2.7
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L - EPSS
- 0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)
- CWE
- CWE-20
- Published
- Modified
- Record from
- the NVD, synced
Affected
- element:synapse
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-6qf2-7x63-mm6v | PyPI | matrix-synapse | <1.152.1 | 1.152.1 |
| PYSEC-2026-194 | PyPI | matrix-synapse | <1.152.1 | 1.152.1 |