CVE-2026-45076

published 2026-05-28

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…

medium 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 E X CR X IR X AR X MAV X MAC X MAT X MPR X MUI X MVC X MVI X MVA X MSC X MSI X MSA X S X AU X R X V X RE X U X

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.

Affected

2 ranges

Vendor	Product	Version range	Fixed in
debian	matrix-synapse	>= 0 < 1.152.1	1.152.1
element-hq	synapse	< 1.152.1	1.152.1

CWE-20