CVE-2026-69198ip-address: a CIDR suffix on the parsed address suppresses special-use classification and can bypass SSRF and trust-boundary checks

Official description

ip-address is a library for parsing and manipulating IPv4 and IPv6 addresses in JavaScript. From 10.1.1 until 10.2.2, every special-use classification method is built on isInSubnet, which short-circuits to false whenever the address's own subnet mask is shorter than the reference range's mask. That mask comes verbatim from the CIDR suffix on the parsed input, so appending a suffix such as /0 suppresses classification entirely: isLoopback(), isPrivate(), isLinkLocal(), isCGNAT(), isMulticast(), isUnspecified(), isBroadcast(), isULA(), and getType() all report an internal address as unremarkable, while correctForm() and address still return the real internal target. An application that builds a network trust-boundary decision on these checks, for example a filter intended to block Server-Side Request Forgery, or SSRF, may therefore treat an internal target as external and allow the request. The underlying bit comparison is correct, and mask(n) already returns the first n bits of the full parsed address independently of subnetMask; the defect is solely that the containment guard sits in the classification path. This issue is fixed in version 10.2.2.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/beaugunderson/ip-address/security/advisories/GHSA-4xrf-jv44-h6hh x_refsource_CONFIRM
• https://github.com/beaugunderson/ip-address/commit/488fe9bc7c35363b4b090494fc38c266d217740d x_refsource_MISC
• https://github.com/beaugunderson/ip-address/releases/tag/v10.2.2 x_refsource_MISC