Synapse's invalid device keys degrade federation functionality

보통 5.3CVE-2025-61672 · GHSA-fh66-fcv5-jjfr · PYSEC-2026-1612 · Published 08/10/2025 · updated 08/10/2026

요약

CVE-2025-61672은(는) matrix-synapse에 영향을 주는 보통 (CVSS 5.3) 취약점입니다.
향후 30일 내 악용 확률(EPSS): 0.48%, 전체 취약점의 41.2%보다 높음.
조치: 1.139.1, 1.138.3 이상으로 업데이트하세요.

Package	Affected versions	Patched versions
matrix-synapse PyPI	`≥ 1.139.0rc2, < 1.139.1< 1.138.3`	`1.139.11.138.3`

Description

Impact

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.

Patches

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, it is recommend to skip these releases and upgrading straight to 1.138.4 and 1.139.2.

Workarounds

The vulnerability can only be exploited by users registered on the victim homeserver.

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.