Bug 2402525 (CVE-2025-61672) - CVE-2025-61672 matrix-synapse: Synapse: Lack of device key validation leads to federation degradation
Summary: CVE-2025-61672 matrix-synapse: Synapse: Lack of device key validation leads t...
Keywords:
Status: NEW
Alias: CVE-2025-61672
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
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Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-10-08 16:01 UTC by OSIDB Bzimport
Modified: 2025-12-02 23:17 UTC (History)
0 users

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Description OSIDB Bzimport 2025-10-08 16:01:18 UTC 
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.
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