CVE-2025-30355

Synapse vulnerable to federation denial of service via malformed events

State: Published
Severity: 7.1 High
Published: Mar 27, 2025
Updated: Mar 27, 2025
Reserved: Mar 21, 2025

Description

Synapse is an open source Matrix homeserver implementation. A malicious server can craft events which, when received, prevent Synapse version up to 1.127.0 from federating with other servers. The vulnerability has been exploited in the wild and has been fixed in Synapse v1.127.1. No known workarounds are available.

Scores

CVSS	Score	Vector	Source
3.1	7.1 High	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H	GitHub_M

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
synapseelement-hq	< 1.127.1Affected

References

https://github.com/element-hq/synapse/security/advisories/GHSA-v56r-hwv5-mxg6
https://github.com/element-hq/synapse/commit/2277df2a1eb685f85040ef98fa21d41aa4cdd389
https://github.com/element-hq/synapse/releases/tag/v1.127.1

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