vulnerability / NVI-00015046 / Revision 1
DOMPurify: IN_PLACE hook removal leaves a detached subtree executable, causing XSS
GitHub lists this reviewed advisory for dompurify. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
dompurify
source listed<= 3.4.12
### Summary During `IN_PLACE` sanitization, a hook that removes an element can leave that element's detached descendants executable. A descendant image can retain its attacker-provided `onload` handler and fire after `sanitize()` returns, even though the returned root is clean and the image remains disconnected from the document. ### Details In DOMPurify 3.4.12, `_sanitizeElements()` in `src/purify.ts:1862-1904` runs the `beforeSanitizeElements` or `uponSanitizeElement` hook and returns immediately when the hook detached the current node. The return does not call `_neutralizeSubtree(currentNode)`. The detached subtree is not added to `DOMPurify.removed`, so the post-walk `IN_PLACE` neutralization cannot reach it. If the browser queued a resource event while the application constructed the detached dirty root, a descendant can therefore retain its handler and execute after sanitization. The hook only rejects the containing element and does not add or approve the event handler. DOMPurify's ordinary removal path de-arms the same queued event; only the hook-detachment early return skips the existing subtree neutralization. ### PoC Load the published `dompurify@3.4.12` `dist/puri
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-55q2-fjhq-7xh7 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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