Vulnerability · Published Sep 28, 2026 · Assigned by GitHub_M
CVE-2026-101912ip-address: isInSubnet() and isHostInSubnet() compare addresses of different families as if they shared an address space, allowing an allowlist check to admit an address outside its range
Medium 6.3
In plain English
A medium-severity type confusion in ip-address from beaugunderson. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
ip-address is a library for parsing and manipulating IPv4 and IPv6 addresses in JavaScript. Prior to 10.7.1, the isInSubnet and isHostInSubnet methods in src/common.ts compare masked binary strings without validating that both operands use the same IP family. A cross-family containment check whose leading address bits match makes the masked strings compare equal even though IPv4 and IPv6 do not share an address space. An allowlist or denylist decision can therefore classify an address outside the intended range as contained. This issue is fixed in version 10.7.1.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | node-ip-address | no fix listed | DEBIAN-CVE-2026-101912 |
| Debian:13 | node-ip-address | no fix listed | DEBIAN-CVE-2026-101912 |
| Debian:14 | node-ip-address | 10.7.2-1 | DEBIAN-CVE-2026-101912 |
| Ubuntu:22.04:LTS | node-ip-address | no fix listed | UBUNTU-CVE-2026-101912 |
| Ubuntu:24.04:LTS | node-ip-address | no fix listed | UBUNTU-CVE-2026-101912 |
| Ubuntu:26.04:LTS | node-ip-address | no fix listed | UBUNTU-CVE-2026-101912 |
| Ubuntu:26.10 | node-ip-address | no fix listed | UBUNTU-CVE-2026-101912 |
| npm | ip-address | 10.7.1 | GHSA-j6r3-76f7-8jcv |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| beaugunderson | ip-address | < 10.7.1 |
Weakness: CWE-697, CWE-843 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N