CVE-2025-61672

Synapse is an open source Matrix homeserver implementation. Lack of validation for device keys in Synapse before 1.138.3 and in Synapse 1.139.0 allow an attacker registered on the victim homeserver to degrade federation functionality, unpredictably breaking outbound federation to other homeservers. The issue is patched in Synapse 1.138.3, 1.138.4, 1.139.1, and 1.139.2. Note that even though 1.138.3 and 1.139.1 fix the vulnerability, they inadvertently introduced an unrelated regression. For this reason, the maintainers of Synapse recommend skipping these releases and upgrading straight to 1.138.4 and 1.139.2.

CVSS

No CVSS.

References

Link	Resource
https://github.com/element-hq/synapse/commit/26aaaf9e48fff80cf67a20c691c75d670034b3c1
https://github.com/element-hq/synapse/commit/7069636c2d6d1ef2022287addf3ed8b919ef2740
https://github.com/element-hq/synapse/pull/17097
https://github.com/element-hq/synapse/releases/tag/v1.138.3
https://github.com/element-hq/synapse/releases/tag/v1.139.1
https://github.com/element-hq/synapse/security/advisories/GHSA-fh66-fcv5-jjfr

Configurations

No configuration.

History

08 Oct 2025, 15:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2025-10-08 15:16

Updated : 2025-10-08 19:38

NVD link : CVE-2025-61672

Mitre link : CVE-2025-61672

CVE.ORG link : CVE-2025-61672

JSON object : View

Products Affected

No product.

CWE

CWE-1287

Improper Validation of Specified Type of Input

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