CVE-2026-101912

ip-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

Published Sep 28, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-j6r3-76f7-8jcv ip-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
History
Type Values Removed Values Added
Weaknesses CWE-1024
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}

threat_severity

Moderate

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Beaugunderson
Beaugunderson ip-address
Vendors & Products Beaugunderson
Beaugunderson ip-address
Type Values Removed Values Added
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.
Title ip-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
Weaknesses CWE-697
CWE-843
References
Metrics cvssV4_0

{'score': 6.3, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 28, 2026, 7:13 PM
Reserved
Sep 28, 2026, 3:55 PM
Status
Deferred
Published
Sep 28, 2026, 6:17 PM
Modified
Sep 30, 2026, 7:57 PM
Severity
Moderate
Public date
Sep 28, 2026, 5:48 PM