CVE-2026-53450 Details
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.
A vulnerability in Coturn prior to version 4.13.0 allows authenticated TURN clients to bypass default protections against loopback peers. Coturn, an open-source TURN and STUN server implementation, normally rejects loopback peers unless the 'allow-loopback-peers' option is enabled. However, this default rejection can be circumvented by using the IPv4-mapped IPv6 address '::ffff:127.0.0.1' in a TURN XOR-PEER-ADDRESS attribute. The issue arises because the loopback address check prioritizes the literal IPv6 loopback format, failing to recognize the mapped IPv4 equivalent as loopback. This oversight enables an authenticated TURN client to access services bound to localhost on the Coturn host via TURN relay traffic.
Users can upgrade to Coturn version 4.13.0 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 10, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/coturn/coturn/security/advisories/GHSA-w4hf-cr3w-6h79 | CISA-ADP | Third Party Advisory |
| https://github.com/coturn/coturn/commit/b057acbebe721c8f2f202ddad5e16289e295c754 | [email protected] | Patch |
| https://github.com/coturn/coturn/security/advisories/GHSA-w4hf-cr3w-6h79 | [email protected] | Third Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-918 | Server-Side Request Forgery (SSRF) | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| coturn project coturn | < 4.13.0 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 16, 2026 | Initial Analysis | [email protected] |
| Jul 10, 2026 | CVE Modified | CISA-ADP |
| Jul 10, 2026 | New CVE Received | [email protected] |