ip-address has XSS in Address6 HTML-emitting methods

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-42338: 0.47% estimated exploitation activity in the next 30 days; percentile 40.77 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Address6.group() and Address6.link() do not HTML-escape attacker-controlled content before embedding it in the HTML strings they return, and AddressError.parseMessage (emitted by the Address6 constructor for invalid input) can contain unescaped attacker-controlled content in one branch. An application that (1) passes untrusted input to Address6 and (2) renders the output of these methods, or the thrown error's parseMessage, as HTML (e.g. via innerHTML) is vulnerable to cross-site scripting. A related issue in v6.helpers.spanAll() produced malformed markup but was not exploitable; it is hardened in the same release for consistency. Details Four related issues were identified and fixed together: 1. Address6.group(): zone ID injection. The Address6 constructor stores the raw input (including any IPv6 zone ID) in this.address before zone stripping. group() then passed this.address to helpers.simpleGroup(), which wrapped each :-separated segment in a <span element without…

Published by the source

5 May 2026, 21:50 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-v2v4-37r5-5v8g

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-v2v4-37r5-5v8g

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# Patch Next advisory brief: CVE-2026-42338

Advisory: ip-address has XSS in Address6 HTML-emitting methods
IDs: CVE-2026-42338, GHSA-v2v4-37r5-5v8g
Record: https://patchnext.com/advisories/cve-2026-42338 (revision 3, source checked 26 Oct 2026, 12:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ip-address 10.1.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm ip-address: affected <= 10.1.0; fixed in 10.1.1

## Suggested inspection (read-only)
- `npm ls ip-address --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ip-address.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-v2v4-37r5-5v8g (OSV record GHSA-v2v4-37r5-5v8g lists affected ranges: npm ip-address >=0 <10.1.1 (fixed))
- Verified: https://github.com/advisories/GHSA-v2v4-37r5-5v8g (GitHub-reviewed advisory GHSA-v2v4-37r5-5v8g lists affected ranges: npm ip-address >=0 <=10.1.0)

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