Incorrect authorization in coTURN - #VU140951
Published: August 5, 2026
Vulnerability identifier: #VU140951
CSH Severity: Low
CVSS v4: 2.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-863
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to bypass IPv6 peer address restrictions and reach an intended-denied service through TURN relaying.
The vulnerability exists due to incorrect authorization in addr_less_eq() in src/client/ns_turn_ioaddr.c when evaluating non-prefix-aligned IPv6 min-max peer ranges. A remote user can send CONNECT and CONNECTION-BIND requests for a crafted IPv6 peer address to bypass IPv6 peer address restrictions and reach an intended-denied service through TURN relaying.
Exploitation requires a custom non-prefix-aligned IPv6 min-max rule and a reachable peer service from the Coturn server. Exact-address and ordinary prefix-aligned controls are not affected in the same way.
Affected software
coTURN
Remediation
Install security update from vendor's website.
coTURN - update to 4.16.0