CVE-2026-54272
CVE-2026-54272 is a Improper Input Validation vulnerability in ip-address. O3 Security confirms whether CVE-2026-54272 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
ip-address: Misclassification of IPv4-mapped/NAT64 IPv6 addresses can bypass SSRF and trust-boundary checks
Real-World Exposure
ip-addressReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects npm packages — download data is not available via public APIs for these ecosystems.
Description
ip-address is a library for parsing and manipulating IPv4 and IPv6 addresses in JavaScript. Versions 10.1.1 through 10.2.0 are vulnerable to SSRF through misclassification of IPv4-mapped/NAT64 IPv6 addresses. Address6.getType() classifies an address by matching it against a table of known IPv6 special-use prefixes, returning Global unicast when nothing matches. That table had no entry for the IPv4-mapped range (::ffff:0:0/96), so every mapped address fell through to Global unicast; NAT64 addresses matched their own NAT64 … labels. The boolean checks isLoopback, isUnspecified, and isMulticast compared getType() against a fixed label and so returned false, while isLinkLocal and isULA checked only the native IPv6 ranges. The library already exposed isMapped4() and to4(), but did not apply them inside these checks, so a mapped or NAT64 address was never normalized to its embedded IPv4 address before classification. For IPv4-mapped addresses the host OS routes to the IPv4 stack, so the misclassification is reachable on any dual-stack host. For NAT64, the classification bypass is unconditional but end-to-end reachability additionally requires a NAT64/DNS64 gateway in the deployment network.This issue has been fixed in version 10.2.1.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | ip-address | ≥ 10.1.1&&< 10.2.1 | 10.2.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ip-address. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update ip-address to 10.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54272 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-54272 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-54272. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-54272 in your dependencies?
O3 detects CVE-2026-54272 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.