What’s Vulnerable › Vulnerabilities

CVE-2026-101910: ip-address: no classifier recognizes the NAT64 local-use range 64:ff9b:1::/48, allowing SSRF and trust-boundary bypass

• Severity: medium (CVSS 6.9 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: 2026-09-28 · updated 2026-09-30
• Weakness: CWE-918

Description

ip-address is a library for parsing and manipulating IPv4 and IPv6 addresses in JavaScript. From 10.2.0 until 10.5.1, the Address6 isPrivate classifier in src/ipv6.ts does not recognize the NAT64 local-use range 64:ff9b:1::/48. Applications that combine isPrivate, isLoopback, and isLinkLocal for a trust-boundary decision can treat an internal IPv4 destination encoded through that range as external. Exploitation depends on a server network using an operator-selected NAT64 prefix within the local-use range. A successful bypass can cross the intended network trust boundary. This issue is fixed in version 10.5.1.

Affected products

• beaugunderson ip-address: from 10.2.0, < 10.5.1

References

• https://github.com/beaugunderson/ip-address/commit/ab3dc88bcf5374344168a2ba075ca7ac4ff257f8
• https://github.com/beaugunderson/ip-address/releases/tag/v10.5.1
• https://github.com/beaugunderson/ip-address/security/advisories/GHSA-2vr4-cq9g-pvrc
• https://github.com/beaugunderson/ip-address/security/advisories/GHSA-2vr4-cq9g-pvrc

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