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Coturn: Prior to 4.16.0, dtls_server_input_handler() and create_new_connected_udp_socket() in src/apps/relay/dtls_listener.c retain OpenSSL… (CVE-2026-73214)

0
Medium
VulnerabilityCVE-2026-73214gcveosvubuntu-cve-2026-73214cve-2026-73214ubuntu-16-04-ltsubuntu-18-04-ltsubuntu-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-26-10ubuntu-26-04-lts
Published: 08/11/2026 (08/11/2026, 18:18:00 UTC)
Source: GCVE Database
Product: coturn

Description

Coturn versions prior to 4.16.0 contain a vulnerability in dtls_server_input_handler() and create_new_connected_udp_socket() functions that improperly retain OpenSSL dtls1_reassemble_fragment() state for a large fragmented ClientHello message. This allows an unauthenticated remote attacker to exhaust server memory by sending crafted UDP packets without needing TURN credentials or completing a handshake. The issue is fixed in Coturn version 4.16.0.

CVSS v4.0

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vuln. Confidentiality
None
Vuln. Integrity
None
Vuln. Availability
High
Subsq. Confidentiality
None
Subsq. Integrity
None
Subsq. Availability
None
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Affected software

Ubuntu:16.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=xenial
Affected versions
=4.4.5.4-2=4.5.0.2-3=4.5.0.3-1=4.5.0.3-1build1=4.5.0.3-1ubuntu0.2=4.5.0.3-1ubuntu0.3=4.5.0.3-1ubuntu0.4
Ubuntu:18.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=bionic
Affected versions
=4.5.0.6-1ubuntu2=4.5.0.7-1ubuntu1=4.5.0.7-1ubuntu2=4.5.0.7-1ubuntu2.18.04.1=4.5.0.7-1ubuntu2.18.04.2=4.5.0.7-1ubuntu2.18.04.3
Ubuntu:20.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=focal
Affected versions
=4.5.1.1-1.1build1=4.5.1.1-1.1build2=4.5.1.1-1.1ubuntu0.20.04.1=4.5.1.1-1.1ubuntu0.20.04.2
Ubuntu:22.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=jammy
Affected versions
=4.5.2-3=4.5.2-3.1~ubuntu22.04.1
Ubuntu:24.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=noble
Affected versions
=4.6.1-1build1=4.6.1-1build2=4.6.1-1build3=4.6.1-1build4
Ubuntu:26.10more threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=stonking
Affected versions
=4.6.1-2build2=4.12.0-1=4.14.0-1=4.15.0-1=4.18.0-1
Ubuntu:26.04:LTSmore threats →ghsa
coturn
pkg:deb/ubuntu/coturn?arch=source&distro=resolute
Affected versions
=4.6.1-2build1=4.6.1-2build2

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AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 10/17/2026, 23:47:48 UTC

Technical Analysis

Coturn, an open source TURN and STUN server implementation, has a vulnerability in versions before 4.16.0 where the functions 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 message that declares a 650,000-byte handshake before cookie validation. This flaw allows an unauthenticated remote sender using fresh UDP tuples to cause memory exhaustion on the server without requiring TURN credentials, a completed handshake, a valid cookie, or source IP spoofing. The vulnerability is addressed in Coturn 4.16.0.

Potential Impact

An unauthenticated remote attacker can cause memory exhaustion on affected Coturn servers by sending specially crafted fragmented ClientHello messages over UDP. This can lead to denial of service conditions without needing valid credentials or completing the DTLS handshake.

Mitigation Recommendations

Upgrade Coturn to version 4.16.0 or later, where this vulnerability is fixed. No other mitigation or workaround is indicated.

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Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-73214
Osv Schema Version
1.7.0
Ecosystems
["Ubuntu:16.04:LTS","Ubuntu:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:26.10","Ubuntu:26.04:LTS"]
Cvss Version
4.0

Threat ID: 6ad3f58b2cdf04f6566621c0

Added to database: 10/17/2026, 22:24:11 UTC

Last enriched: 10/17/2026, 23:47:48 UTC

Last updated: 10/17/2026, 23:47:48 UTC

Views: 3

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