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.
- Published
- 2026-08-03 20:17:30
- Last modified
- 2026-08-04 18:16:56
- Vector
- CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X