Review reviewHigh

CVE-2026-53450

coturn

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....

CVSS: 7.4
EPSS: 0.17%
CISA KEV: Not listed
Published: 2026.07.11

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.17%

Technical severityCVSS 7.4

Vulnerability overview

Affected product and versions

Product: coturn
Affected versions: >= < 4.13.0, < 4.13.0
Fixed versions: 4.13.0

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that coturn and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L
CWE: CWE-918