VDB

CVE-2025-61672

CVE-2025-61672 PUBLISHED CVSS 5.300000190734863 MEDIUM

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.

EPSS 0.47% · 40.0th percentile

Risk Scores

CVSS 4.0
5.300000190734863
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
EPSS Score
0.47%
40.0th percentile

Affected Products

VendorProductVersions
element-hqsynapse< 1.138.3, = 1.139.0
PyPImatrix-synapse0, 1.139.0rc2

Timeline

  • Jan 21, 1970 Security Advisory
  • Oct 7, 2025 CVE Published
  • Oct 9, 2025 EPSS Score
  • Oct 16, 2025 EPSS Score
  • Oct 23, 2025 EPSS Score
  • Oct 31, 2025 EPSS Score
  • Nov 7, 2025 EPSS Score
  • Nov 14, 2025 EPSS Score
  • Nov 21, 2025 EPSS Score
  • Nov 28, 2025 EPSS Score
  • Dec 5, 2025 EPSS Score
  • Dec 13, 2025 EPSS Score

References

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