Patch Forecast
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CVE-2026-101910 · GHSA-2vr4-cq9g-pvrc

ip-address: no classifier recognizes the NAT64 local-use range 64:ff9b:1::/48, allowing SSRF and trust-boundary bypass

Risk score
58/100
CVSS
6.9 v4.0
Exploit chance (30 days)
0.4%
Published
28 Sep 2026

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What to know

What it is
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 decis…
Affected
ip-address (npm) >= 10.2.0, <= 10.5.0
Fix
Upgrade ip-address to 10.5.1 or later.
Exploitation
Public proof of concept

Story map

Story map: ip-addressTHE FLAWSTHE FIXCVE-2026-101910No classifier recognizes theNAT64 local-use range64:ff9b:1::/48, allowing SSRF…CVSS 6.9 · EPSS 0%CVE-2026-101913Address6.isLinkLocal()recognizes fe80::/64 ratherthan fe80::/10, allowing SSRF…CVSS 6.3 · EPSS 0%CVE-2026-101912IsInSubnet() andisHostInSubnet() compareaddresses of different…CVSS 6.3 · EPSS 0%CVE-2026-101911Address6 builds a parsediagnostic proportional to theinput with no length bound…CVSS 6.3 · EPSS 0%Upgrade ip-address10.5.1 · 10.7.1or later on your release lineWho is exposedip-address (npm) >= 10.2.0, <=10.5.0YELLOW · PLAN IT INip-addressip-address is a library forparsing and manipulating IPv4and IPv6 addresses inJavaScript. From 10.2.0 until10.5.1, the Address6 isPrivateclassifier in src/ipv6.ts doesnot recognize the NAT64…Where it standsPublic proof of conceptCONNECTS TOSame weaknessServer-side request forgery (CWE-918)220 other warnings in 30 days →
Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

ip-address: Yellow, plan it in. 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 decis…

The flaws

  • CVE-2026-101910: No classifier recognizes the NAT64 local-use range 64:ff9b:1::/48, allowing SSRF and trust-boundary bypass (CVSS 6.9 · EPSS 0%)
  • CVE-2026-101913: Address6.isLinkLocal() recognizes fe80::/64 rather than fe80::/10, allowing SSRF and trust-boundary bypass to on-link hosts (CVSS 6.3 · EPSS 0%)
  • CVE-2026-101912: 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 (CVSS 6.3 · EPSS 0%)
  • CVE-2026-101911: Address6 builds a parse diagnostic proportional to the input with no length bound, allowing a single long string to stall or crash the process (CVSS 6.3 · EPSS 0%)

The fix

Upgrade ip-address: 10.5.1 · 10.7.1 or later on your release line

Who is exposed: ip-address (npm) >= 10.2.0, <= 10.5.0

Where it stands

  • Public proof of concept

Connects to

Why it is Yellow

  • CVSS 6.9 medium
  • Public exploit or proof of concept referenced
  • On your watchlist: npm

Affected packages

PackageEcosystemVulnerableFixed in
ip-addressnpm>= 10.2.0, <= 10.5.010.5.1

References

Original 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.

Last activity 28 Sep 2026. Patch Forecast updates every hour.