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CVE-2026-68552

Coturn: uint16_t truncation overflow in STUN message length causes TCP stream framing bypass

5.3 MediumFix available

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
Low

Exploit likelihood

0.52%Up 0.2 points since Aug 20, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.3

Coturn: uint16_t truncation overflow in STUN message length causes TCP stream framing bypass

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
CVE-2026-68552
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-190
Updated
2026-11-02
EUVDEUVD-2026-63079 5.3

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
EUVD-2026-63079
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
NVD 5.3

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
CVE-2026-68552
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-190
Updated
2026-11-02
OSV 5.3

Coturn: uint16_t truncation overflow in STUN message length causes TCP stream framing bypass

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
CVE-2026-68552
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness
CWE-190
Updated
2026-11-02
OSVDEBIAN-CVE-2026-68552 5.3

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
DEBIAN-CVE-2026-68552
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVUBUNTU-CVE-2026-68552 5.3

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an unauthenticated remote client can send a STUN message over TCP or TLS with a body-length field from 65520 through 65532, causing the uint16_t len variable in stun_get_message_len_str() in src/client/ns_turn_msg.c to wrap when STUN_HEADER_LENGTH is added. The framing layer then consumes only 4 through 16 bytes, treats the remaining bytes as another message, desynchronizes the stream parser, and drops the attacking client's connection. Other clients and the server process are not affected. This issue is fixed in version 4.15.0.

Record
UBUNTU-CVE-2026-68552
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Updated
2026-11-02
OSVopenSUSE-SU-2026:11617-1 No score

coturn-4.17.2-1.1 on GA media

These are all security issues fixed in the coturn-4.17.2-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:11617-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
coturn
Debian:12
All versions, plus listed versions
4.12.0-14.14.0-14.15.0-14.18.0-14.6.1-14.6.1-2
None known
coturn
Debian:13
All versions, plus listed versions
4.12.0-14.14.0-14.15.0-14.18.0-14.6.1-2
None known
coturn
Debian:14
before 4.15.0-1, plus listed versions
4.12.0-14.14.0-14.6.1-2
4.15.0-1
coturn
Ubuntu:16.04:LTS
All versions, plus listed versions
4.4.5.4-24.5.0.2-34.5.0.3-14.5.0.3-1build14.5.0.3-1ubuntu0.24.5.0.3-1ubuntu0.34.5.0.3-1ubuntu0.4
None known
coturn
Ubuntu:18.04:LTS
All versions, plus listed versions
4.5.0.6-1ubuntu24.5.0.7-1ubuntu14.5.0.7-1ubuntu24.5.0.7-1ubuntu2.18.04.14.5.0.7-1ubuntu2.18.04.24.5.0.7-1ubuntu2.18.04.3
None known
coturn
Ubuntu:20.04:LTS
All versions, plus listed versions
4.5.1.1-1.1build14.5.1.1-1.1build24.5.1.1-1.1ubuntu0.20.04.14.5.1.1-1.1ubuntu0.20.04.2
None known
coturn
Ubuntu:22.04:LTS
All versions, plus listed versions
4.5.2-34.5.2-3.1~ubuntu22.04.1
None known
coturn
Ubuntu:24.04:LTS
All versions, plus listed versions
4.6.1-1build14.6.1-1build24.6.1-1build34.6.1-1build4
None known
coturn
Ubuntu:26.10
All versions, plus listed versions
4.6.1-2build24.12.0-14.14.0-14.15.0-14.18.0-1
None known
coturn
Ubuntu:26.04:LTS
All versions, plus listed versions
4.6.1-2build14.6.1-2build2
None known
coturn
openSUSE:Tumbleweed
From an advisory covering 17 CVEs
before 4.17.2-1.1
4.17.2-1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-68552 is a medium vulnerability (CVSS 5.3) in Coturn, published August 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.52%, the 44th percentile. Fixed in coturn 4.15.0-1.

References

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