CVE-2025-61672

Oct. 8, 2025, 7:38 p.m.

5.3
Medium

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.

Product(s) Impacted

Vendor Product Versions
Element
  • Matrix Synapse
  • 1.138.3, 1.138.4, 1.139.1, 1.139.2

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-1287
Improper Validation of Specified Type of Input
The product receives input that is expected to be of a certain type, but it does not validate or incorrectly validates that the input is actually of the expected type.

*CPE(s)

Affected systems and software identified for this CVE.

Type Vendor Product Version Update Edition Language Software Edition Target Software Target Hardware Other Information
a element matrix_synapse 1.138.3 / / / / / / /
a element matrix_synapse 1.138.4 / / / / / / /
a element matrix_synapse 1.139.1 / / / / / / /
a element matrix_synapse 1.139.2 / / / / / / /

References

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

Tags

security-advisories@github.com
CWE-1287
2025-10-08
CVE-2025-61672

CVSS Score

5.3 / 10

CVSS Data - 4.0

  • Attack Vector: NETWORK
  • Attack Complexity: LOW
  • Attack Requirements: NONE
  • Privileges Required: LOW
  • User Interaction: NONE
  • Scope:
  • Confidentiality Impact: NONE
  • Integrity Impact: LOW
  • Availability Impact: LOW
  • Exploit Maturity: NOT_DEFINED

    • 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

    View Vector String

Timeline

Published: Oct. 8, 2025, 3:16 p.m.
Last Modified: Oct. 8, 2025, 7:38 p.m.

Status : Awaiting Analysis

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

security-advisories@github.com

*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.