Server-Side Request Forgery (SSRF) in coTURN - CVE-2026-53450
Published: June 30, 2026
Vulnerability identifier: #VU135962
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:L/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-53450
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: coTURN
Affected software:
coTURN
coTURN
Detailed vulnerability description
The vulnerability allows a remote user to access localhost-bound services through TURN relay traffic.
The vulnerability exists due to server-side request forgery (SSRF) in the loopback peer protection in good_peer_addr() and ioa_addr_is_loopback() when processing a TURN XOR-PEER-ADDRESS containing the IPv4-mapped IPv6 address ::ffff:127.0.0.1. A remote user can request a permission or channel binding for the mapped loopback address to access localhost-bound services through TURN relay traffic.
The issue affects the default loopback peer guard and does not apply when an explicit denied-peer range covering 127.0.0.0/8 is configured.
How to mitigate CVE-2026-53450
Install security update from vendor's website.