---
id: CVE-2026-73214
title: Coturn is a free open source implementation of TURN and STUN Server
summary: >-
  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 fo…
severity: none
cwe:
  - CWE-400
  - CWE-770
published: '2026-08-11'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T20:55:04.493'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-73214'
references:
  - url: >-
      https://github.com/coturn/coturn/commit/37e13d1d60af8f1422c01b5e9f1c6bc355d03b85
    label: security-advisories@github.com
  - url: >-
      https://github.com/coturn/coturn/commit/beb4de9dcb6a475129595b943c9a34264420df09
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/pull/2003'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/pull/2012'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/releases/tag/4.16.0'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/security/advisories/GHSA-5x2p-4vqj-f6m4'
    label: security-advisories@github.com
tags:
  - nvd
epss: 0.00577
epssPercentile: 0.452
ingestedAt: '2026-09-09T21:22:45.529Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.