What’s Vulnerable › Vulnerabilities

CVE-2026-73213: 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)

• Severity: medium (CVSS 5.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-11 · updated 2026-09-09
• Weakness: CWE-863

Description

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.

Affected products

• coturn: before 4.16.0

References

• https://github.com/coturn/coturn/commit/6c13608c28a04af5d63abddd7565a0dcc4771c28
• https://github.com/coturn/coturn/releases/tag/4.16.0
• https://github.com/coturn/coturn/security/advisories/GHSA-4v97-rxjj-4f99
• https://github.com/coturn/coturn/security/advisories/GHSA-4v97-rxjj-4f99

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