NAT64 Local-Use Range Bypass in ip-address Library by Beau Gunderson
CVE-2026-101910

6.9MEDIUM

Key Information:

Vendor

Beaugunderson

Status
Ip-address
Vendor
CVE Published:
28 September 2026

What is CVE-2026-101910?

The ip-address library for JavaScript, specifically from versions 10.2.0 to 10.5.1, allows an Address6 isPrivate classifier to misinterpret the NAT64 local-use range 64:ff9b:1::/48. This can lead to applications erroneously treating internal IPv4 destinations, encoded via that range, as external, effectively breaching trust boundaries within a server network. Exploitation is contingent upon the deployment of a user-defined NAT64 prefix within the local-use space. Version 10.5.1 rectifies this vulnerability.

Affected Version(s)

ip-address >= 10.2.0, < 10.5.1

References

https://github.com/beaugunderson/ip-address/security/advi...
x_refsource_CONFIRM
https://github.com/beaugunderson/ip-address/commit/ab3dc8...
x_refsource_MISC
https://github.com/beaugunderson/ip-address/releases/tag/...
x_refsource_MISC

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.