CVE-2026-101910 ip-address: no classifier recognizes the NAT64 local-use range 64:ff9b:1::/48, allowing SSRF and trust-boundary bypass
Attackers can bypass network trust boundaries in applications using this library if NAT64 local-use ranges are configured, potentially accessing internal resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-101910?
CVE-2026-101910 is a medium-severity server-side request forgery vulnerability in beaugunderson ip-address, published on 28 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-101910?
2 open source packages ship an affected version, including ip-address.
| Package | Affected | Fixed in |
|---|---|---|
ip-address npm | From 10.2.0 | 10.5.1 |
ip-address npm | From 10.2.0 | 10.5.1 |
How do I fix CVE-2026-101910?
Upgrade ip-address to 10.5.1 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-101910 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101910 exists.
Sources
Also known as CLEANSTART-2026-BJ83966, CLEANSTART-2026-ED95954, CLEANSTART-2026-PU19584, DEBIAN-CVE-2026-101910, ECHO-5e25-ee30-5fe8, GHSA-2vr4-cq9g-pvrc and 16 more.