The Coturn TURN Server is a VoIP media traffic NAT traversal server and gateway.
It can be used as a general-purpose network traffic TURN server/gateway, too.
This implementation also includes some extra features. Supported RFCs:
TURN specs:
- RFC 5766 - base TURN specs
- RFC 6062 - TCP relaying TURN extension
- RFC 6156 - IPv6 extension for TURN
- Experimental DTLS support as client protocol.
STUN specs:
- RFC 3489 - "classic" STUN
- RFC 5389 - base "new" STUN specs
- RFC 5769 - test vectors for STUN protocol testing
- RFC 5780 - NAT behavior discovery support
The implementation fully supports the following client-to-TURN-server protocols:
- UDP (per RFC 5766)
- TCP (per RFC 5766 and RFC 6062)
- TLS (per RFC 5766 and RFC 6062); TLS1.0/TLS1.1/TLS1.2
- DTLS (experimental non-standard feature)
Supported relay protocols:
- UDP (per RFC 5766)
- TCP (per RFC 6062)
Supported user databases (for user repository, with passwords or keys, if
authentication is required):
- SQLite
- MySQL
- PostgreSQL
- Redis
Redis can also be used for status and statistics storage and notification.
Supported TURN authentication mechanisms:
- long-term
- TURN REST API (a modification of the long-term mechanism, for time-limited
secret-based authentication, for WebRTC applications)
The load balancing can be implemented with the following tools (either one or a
combination of them):
- network load-balancer server
- DNS-based load balancing
- built-in ALTERNATE-SERVER mechanism.
Update Information:
Coturn 4.9.0 Multiple security fixes Fix to Web Admin password check Cleanup of deprecated OpenSSL APIs Fix for CVE-2026-27624: Bypass localhost and IP range block using IPv4-mapped IPv6
* Wed Feb 25 2026 Robert Scheck
[ 1 ] Bug #2442550 - CVE-2026-27624 coturn: IPv4-mapped IPv6 bypasses denied-peer-ip ACL
https://bugzilla.redhat.com/show_bug.cgi?id=2442550
This update can be installed with the "dnf" update program. Use su -c 'dnf upgrade --advisory FEDORA-2026-379e214a37' at the command line. For more information, refer to the dnf documentation available at http://dnf.readthedocs.io/en/latest/command_ref.html#upgrade-command-label
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