CVE-2025-54315: Matrix Specification

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

The Matrix specification before 1.16 (i.e., with a room version before 12) lacks create event uniqueness.

Affected products

• Matrix Matrix Specification: before 1.16 (fixed in 1.16)

Published 2025-10-02. Last modified 2026-10-08.