Is CVE-2025-61672 in the CISA KEV catalog?

No. CVE-2025-61672 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the EPSS score for CVE-2025-61672?

CVE-2025-61672 has an EPSS score of 0.44% (35th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2025-61672?

Upgrade matrix-synapse on debian unstable to 1.139.2-1 or later.

CVE & CISA-KEV Catalog

CVE-2025-61672

UNSCORED

NVD

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.

CWE-1287Improper Validation of Specified Type of Input

How to fix

Remediation Available

matrix-synapseDebian

Fixed in:1.139.2-1CVE-2025-61672

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3.1 Vector

No CVSS vector data available.

Exploit Intelligence

0.44%probability of exploitation in 30 days

35thpercentile

Low risk: more likely to be exploited than 35% of all known CVEs.

References

Other references6

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-10-08.