DOMPurify XSS via selectedcontent re-clone

Exploitation

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

CVSS

8.2 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

EPSS

• CVE-2026-47423: 0.41% estimated exploitation activity in the next 30 days; percentile 35.27 (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 DOMPurify 3.4.4 allows selectedcontent by default, allowing a chain in which browsers "re-clone" an XSS payload after sanitization, effectively bypassing DOMPurify. Details The chain is as follows: 1. The browser parses the input and creates a <selectedcontent clone from the selected <option 2. DOMPurify walks and sanitizes that generated clone. 3. DOMPurify reaches the original <option and removes selected=javascript:1 4. The browser refreshes the <selectedcontent clone from the original option's content. 5. The refreshed clone is in a subtree DOMPurify already walked, which DOMPurify doesn't go back to sanitize 6. The returned string contains unsanitized markup inside <selectedcontent. PoC Observed "sanitized" output in Chromium 148/WebKit 625: After reinsertion, the browser updates the live DOM and strips the handler from the displayed clone, but the onerror has already fired: Reproduced in Chromium and WebKit, but not Safari (not yet latest WebKit) or Firefox. Will likely…

Published by the source

1 Jun 2026, 14:07 UTC

Last modified by the source

1 Jun 2026, 14:26 UTC

Source last checked

26 Oct 2026, 12:52 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-87xg-pxx2-7hvx

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-87xg-pxx2-7hvx

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# Patch Next advisory brief: CVE-2026-47423

Advisory: DOMPurify XSS via selectedcontent re-clone
IDs: CVE-2026-47423, GHSA-87xg-pxx2-7hvx
Record: https://patchnext.com/advisories/cve-2026-47423 (revision 2, 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: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: dompurify 3.4.5. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm dompurify: affected >= 3.4.4, <= 3.4.4; fixed in 3.4.5

## Suggested inspection (read-only)
- `npm ls dompurify --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 dompurify.
- 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-87xg-pxx2-7hvx (OSV record GHSA-87xg-pxx2-7hvx lists affected ranges: npm dompurify >=3.4.4 <3.4.5 (fixed))
- Verified: https://github.com/advisories/GHSA-87xg-pxx2-7hvx (GitHub-reviewed advisory GHSA-87xg-pxx2-7hvx lists affected ranges: npm dompurify >=3.4.4 <=3.4.4)

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