CVE-2026-43994

Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/coturn/coturn/releases/tag/4.10.0
https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5
https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5

Configurations

No configuration.

History

22 Jun 2026, 19:16

Type	Values Removed	Values Added
References	~~() https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5 -~~	() https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5 -

18 Jun 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-18 21:16

Updated : 2026-06-22 19:16

NVD link : CVE-2026-43994

Mitre link : CVE-2026-43994

CVE.ORG link : CVE-2026-43994

JSON object : View

Products Affected

No product.

CWE

CWE-120

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

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