---
id: CVE-2026-68554
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
  4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to
  an authenticated STUN request on plain UDP or TCP, adjust the STUN header
  length, …
severity: low
cvss: 2.3
cvssVector: 'CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N'
cwe:
  - CWE-345
  - CWE-924
vendor: coturn
product: coturn
affected:
  - coturn < 4.15.0
published: '2026-08-19'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:20:38.860'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-68554'
references:
  - url: >-
      https://github.com/coturn/coturn/commit/ab762f334f511ea37ab4b703a47d5d683a5be978
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/releases/tag/4.15.0'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/security/advisories/GHSA-5538-7cxj-5jcc'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/security/advisories/GHSA-5538-7cxj-5jcc'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-08-20T13:31:52.424319Z'
cvssSource: cna
ingestedAt: '2026-09-14T11:12:32.644Z'
epss: 0.00248
epssPercentile: 0.16438
---

## Overview

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to an authenticated STUN request on plain UDP or TCP, adjust the STUN header length, and recompute the unkeyed FINGERPRINT while the original HMAC remains valid because it covers only the message prefix. Server-side parsing in src/server/ns_turn_server.c continues past MESSAGE-INTEGRITY through handle_turn_allocate(), handle_turn_create_permission(), handle_turn_refresh(), and handle_turn_command(), allowing trailing LIFETIME, XOR-PEER-ADDRESS, or ORIGIN attributes to override allocation lifetime, inject a permission, or bypass the origin check. TLS and DTLS deployments prevent this in-transit modification. This issue is fixed in version 4.15.0.

## Remediation

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