Incorrect calculation in Synapse - CVE-2024-31208
Published: April 23, 2024 / Updated: April 23, 2026
Vulnerability identifier: #VU127006
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2024-31208
CWE-ID: CWE-682
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Matrix.org
Affected software:
Synapse
Synapse
Detailed vulnerability description
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper calculation of the auth chain cover index in auth chain indexing when processing specially crafted events from a remote room member. A remote user can send specially crafted events to cause a denial of service.
Exploitation can lead to disk fill and high CPU usage. Servers in private federations, or those that do not federate, are not affected.
How to mitigate CVE-2024-31208
Install security update from vendor's website.