CVE-2025-61672

Synapse: Invalid device keys degrade federation functionality

Published: Oct 8, 2025Updated: Oct 8, 2025 Sources: CVE List NVD GHSACWE-1287

N/ACVSS

NVD MITRE

Description

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.

No summary for this CVE yet.

Weaknesses

CWE-1287

Affected Products

package-ecosystem

oss-project

synapseMixed

Communications / messaging-chat

Exploitability

Official Patch Available

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References

https://github.com/element-hq/synapse/commit/26aaaf9e48fff80cf67a20c691c75d670034b3c1

github.com

https://github.com/element-hq/synapse/commit/7069636c2d6d1ef2022287addf3ed8b919ef2740

github.com

https://github.com/element-hq/synapse/pull/17097

github.com

and 7 more references View all →

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