Executive brief
Coturn is an open-source server used to facilitate audio and video communication (WebRTC) across different network types. A security flaw in its administrative command-line interface allows an authorized administrator to overwrite any file on the server that the Coturn software has permission to access. This could be used to corrupt system configurations, delete security certificates, or cause a service outage.
Technical details
A path traversal and arbitrary file write vulnerability exists in the 'psd' (print sessions dump) command within Coturn's administrative CLI. The 'turn_admin_server.c' component fails to validate the filename argument before passing it to the 'fopen' function with write ('w') permissions. An attacker with valid CLI administrator credentials can exploit this to truncate and overwrite arbitrary files writable by the Coturn process user, such as configuration files or TLS certificates. The attack requires access to the admin interface, which is bound to localhost by default. The issue was resolved in version 4.13.0 by removing the 'psd' command and its associated file-writing functionality.
Affected products
- coturn coturn < 4.13.0
Timeline
- 2026-06-13: patched: Version 4.13.0 released
- 2026-06-26: advisory: GitHub Security Advisory GHSA-jj76-vwjw-w34r published
- 2026-07-10: disclosed: CVE-2026-53449 published to NVD