What’s Vulnerable › Vulnerabilities

CVE-2026-73214: coturn allocates a full per-peer SSL/session before verifying the DTLS cookie, enabling source-spoofing/botnet state-exhaustion DoS

• Severity: high (CVSS 8.2 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-11 · updated 2026-09-09
• Weakness: CWE-400

Description

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.16.0, dtls_server_input_handler() and create_new_connected_udp_socket() in src/apps/relay/dtls_listener.c retain OpenSSL dtls1_reassemble_fragment() state for a 35-byte fragmented ClientHello declaring a 650,000-byte handshake before cookie validation, allowing an unauthenticated remote sender using fresh UDP tuples to exhaust memory without TURN credentials, a completed handshake, a valid cookie, or source spoofing. This issue is fixed in version 4.16.0.

Affected products

• coturn: before 4.16.0

References

• https://github.com/coturn/coturn/commit/37e13d1d60af8f1422c01b5e9f1c6bc355d03b85
• https://github.com/coturn/coturn/commit/beb4de9dcb6a475129595b943c9a34264420df09
• https://github.com/coturn/coturn/pull/2003
• https://github.com/coturn/coturn/pull/2012
• https://github.com/coturn/coturn/releases/tag/4.16.0
• https://github.com/coturn/coturn/security/advisories/GHSA-5x2p-4vqj-f6m4

Get alerted when CVE-2026-73214 or the next vulnerability affects your stack