Is CVE-2025-30355 actively exploited?

CVE-2025-30355 has no public evidence of in-the-wild exploitation as of 2025-08-26.

What is the CVSS score for CVE-2025-30355?

CVE-2025-30355 has a CVSS score of 7.1 (HIGH severity). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H.

How do I patch CVE-2025-30355?

Patch guidance is available from matrix security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2025-30355.

Fix CVE-2025-30355 - HIGH matrix synapse

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H
Attack Vector: network
Complexity: low
Privileges: low
User Action: none
Scope: unchanged
Confidentiality: none
Integrity: low
Availability: high
Weaknesses: CWE-20 · Improper Input ValidationNVD-CWE-noinfo

Metadata

Primary Vendor: MATRIX
Published: 3/27/2025
Last Modified: 8/26/2025
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2025-30355

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary