Bug 2542599 (CVE-2026-101910)

Summary: CVE-2026-101910 ip-address: ip-address: Security boundary bypass via unclassified NAT64 local-use address range
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in ip-address. The address classification mechanism fails to identify the local-use Network Address Translation (NAT64) range as private. A remote attacker can exploit this by submitting an internal address formatted within this IPv6 prefix to an application that relies on the library to enforce network boundaries. Successful exploitation allows an attacker to bypass network access controls, potentially resulting in Server-Side Request Forgery (SSRF) and unauthorized access to restricted internal services.
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Description OSIDB Bzimport 2026-09-28 18:05:09 UTC 
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.