CVE-2026-73213 PUBLISHED

Coturn: `addr_less_eq()` does a component-wise IPv6 comparison instead of a lexicographic one, letting an authenticated TURN client bypass `denied-peer-ip`/`allowed-peer-ip` IPv6 ranges (TURN-specific SSRF)

Assigner: GitHub_M
Reserved: 11.08.2026 Published: 11.08.2026 Updated: 11.08.2026

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.16.0, addr_less_eq() in src/client/ns_turn_ioaddr.c uses a component-wise comparison for native IPv6 min-max intervals in ioa_addr_in_range(), allowing an authenticated TURN client to relay to an IPv6 peer that is numerically within a configured non-prefix-aligned denied-peer-ip range but is classified as outside it. This issue is fixed in version 4.16.0.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CVSS Score: 5.8

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	High
Attack Complexity	Low	Integrity	None	Integrity	High
Attack Requirements	Present	Availability	None	Availability	High
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	coturn
Product	coturn
Versions	Version < 4.16.0 is affected

References

Problem Types

CWE-863: Incorrect Authorization CWE