---
id: CVE-2026-68555
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. In
  4.15.0, an authenticated TURN user can repeatedly resume one allocation from
  fresh UDP 5-tuples without completing a handoff when the server enables
  --mobility. mobi…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-400
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-2026-68555'
references:
  - url: >-
      https://github.com/coturn/coturn/commit/a97f1924bb435bec49d6d91ae01fa2487c2e1bf7
    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-hpq3-g7x4-h7xx'
    label: security-advisories@github.com
  - url: 'https://github.com/coturn/coturn/security/advisories/GHSA-hpq3-g7x4-h7xx'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
epss: 0.0053
epssPercentile: 0.42427
ingestedAt: '2026-09-09T21:22:45.544Z'
---

## Overview

Coturn is a free open source implementation of TURN and STUN Server. In 4.15.0, an authenticated TURN user can repeatedly resume one allocation from fresh UDP 5-tuples without completing a handoff when the server enables --mobility. mobile_begin_transition() in src/server/ns_turn_server.c disarms each new session's allocation timeout and overwrites the allocation's single mobile_pending_resume link, leaving earlier pending sessions unreachable by the cleanup path, while copy_auth_parameters() ignores inc_quota() failure. The attacker can therefore retain unbounded server-side sessions and exhaust process memory even when --user-quota=1 is configured. This issue is fixed in version 4.16.0.

## Remediation

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