CVE-2026-53450

HIGHCVSS 7.4/10EPSS 0.29%

Last modified

CVE-2026-53450 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. 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. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
7.4/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L

EPSS Probability
0.29%

20.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Coturn ProjectCoturn< 4.13.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-53450?
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.
How severe is CVE-2026-53450?
CVE-2026-53450 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.
How do I fix CVE-2026-53450?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST