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TI-2026-38531 Aliases CVE-2026-53450

Coturn: IPv4-mapped 127.0.0.1 bypasses default loopback peer protection

Priority HIGH 66CWE-918Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.0029 21st percentileScored 2026-11-07
Fix Fixed coturn (coturn): 4.13.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
coturncoturnbefore 4.13.04.13.0Patch availableCNA
  • coturn Vendorcoturn Affected before 4.13.0 Fixed in 4.13.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:coturn_project:coturn:*:*:*:*:*:*:*:*before 4.13.0Vulnerablecoturn
  • cpe:2.3:a:coturn_project:coturn:*:*:*:*:*:*:*:* Versions before 4.13.0 Vulnerable ·coturn

Remediation

  • Fix · CNA coturn (coturn) Fixed in 4.13.0

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-53450

References

Patch 1

Advisory 1

  • TI-2026-32037 Coturn: Stack buffer overflow in decode_oauth_token_gcm() CVSS 3.1CRITICAL 9.8
  • TI-2026-29348 Coturn: Misaligned Memory Access in coturn STUN Attribute Parser (Remote DoS on ARM64) CVSS 3.1HIGH 7.5
  • TI-2026-22006 Coturn: IPv4-mapped IPv6 (::ffff:0:0/96) bypasses denied-peer-ip ACL CVSS 3.1HIGH 7.2
  • TI-2026-38529 Coturn: SQL Injection in HTTPS Admin Panel Delete Operations CVSS 3.1HIGH 7.2
  • TI-2026-38530 Coturn: Arbitrary File Write via CLI psd Command CVSS 3.1MEDIUM 6.0
  • TI-2020-04928 Out-of-bounds read in CoTURN CVSS 3.1CRITICAL 9.8
See all 13 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences