SB20260420108 - Multiple vulnerabilities in coTURN

Description

This security bulletin contains information about 2 vulnerabilities.

1) Type conversion (CVE-ID: CVE-2026-40613)

CWE-ID: CWE-704 - Type conversion

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to incorrect type conversion or cast in the STUN attribute parser in src/client/ns_turn_msg.c when processing a crafted STUN message with odd-aligned attribute boundaries. A remote attacker can send a specially crafted UDP packet to cause a denial of service.

Only ARM64/AArch64 deployments with strict alignment enforcement are affected.

2) Stack-based buffer overflow (CVE-ID: CVE-2026-43994)

CWE-ID: CWE-121 - Stack-based buffer overflow

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber

The vulnerability allows a remote attacker to cause a denial of service and potentially execute arbitrary code.

The vulnerability exists due to stack-based buffer overflow in decode_oauth_token_gcm() when processing an attacker-supplied OAuth access token. A remote attacker can send a specially crafted STUN packet containing a crafted OAuth access token to cause a denial of service and potentially execute arbitrary code.

Only servers started with the --oauth mode are vulnerable, and exploitation occurs before AES-GCM authentication is verified.

Remediation

Install update from vendor's website.

References

• https://github.com/coturn/coturn/security/advisories/GHSA-j662-9wcj-mf36
• https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5