Vulnerability Description
Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, coturn rejects loopback peers by default unless allow-loopback-peers is enabled, but the default loopback guard can be bypassed by using the IPv4-mapped IPv6 peer address ::ffff:127.0.0.1 in a TURN XOR-PEER-ADDRESS attribute. ioa_addr_is_loopback checks for the literal IPv6 loopback shape before IPv4-mapped IPv6 handling, so good_peer_addr does not apply the default loopback rejection and an authenticated TURN client can expose services bound only to localhost on the coturn host through TURN relay traffic. This issue is fixed in version 4.13.0.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Coturn Project | Coturn | < 4.13.0 |
Related Weaknesses (CWE)
References
- https://github.com/coturn/coturn/commit/b057acbebe721c8f2f202ddad5e16289e295c754Patch
- https://github.com/coturn/coturn/security/advisories/GHSA-w4hf-cr3w-6h79Third Party Advisory
- https://github.com/coturn/coturn/security/advisories/GHSA-w4hf-cr3w-6h79Third Party Advisory
FAQ
What is CVE-2026-53450?
CVE-2026-53450 is a vulnerability with a CVSS score of 7.4 (HIGH). Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.13.0, coturn rejects loopback peers by default unless allow-loopback-peers is enabled, but the default loopback guard ca...
How severe is CVE-2026-53450?
CVE-2026-53450 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-53450?
Check the references section above for vendor advisories and patch information. Affected products include: Coturn Project Coturn.