CVE-2026-49458
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedDOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(node, { IN_PLACE: true }) accepted same-origin foreign-realm DOM nodes while follow-on checks used parent-realm constructors, causing instanceof checks for forms, named node maps, document fragments, and elements to fail and skip clobber, template-content, and shadow-DOM sanitization branches so executable markup could survive. This issue is fixed in version 3.4.6.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceDOMPurify before 3.4.6 has a bypass vulnerability when using IN_PLACE mode with same-origin foreign-realm DOM nodes. The sanitizer accepts these nodes but subsequent instanceof checks for forms, named node maps, document fragments, and elements fail because they use parent-realm constructors instead of the foreign-realm constructors. This causes clobber, template-content, and shadow-DOM sanitization branches to be skipped, allowing executable markup to survive.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 3.4.6CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify DOMPurify versionCheck package.json dependencies, or run DOMPurify.version in browser console, or inspect the DOMPurify script file for the VERSION propertyAffected if Version is lower than 3.4.6
-
Locate IN_PLACE mode configurationSearch codebase for DOMPurify.IN_PLACE = true or options object containing IN_PLACE: true passed to DOMPurify.sanitize()Affected if IN_PLACE mode is explicitly enabled in the code
-
Identify foreign-realm DOM node usageCheck if the sanitization input includes DOM nodes from a different realm (such as iframes, shadow DOM, or imported nodes from external documents)Affected if Input to DOMPurify.sanitize() contains same-origin foreign-realm nodes while IN_PLACE mode is active
-
Check for affected node type processingInspect sanitization input for presence of form elements, named node maps, document fragments, or shadow DOM contentAffected if Any of these node types are present in input processed with IN_PLACE mode on a vulnerable version
You are affected if DOMPurify version is below 3.4.6 AND your code uses IN_PLACE mode with same-origin foreign-realm DOM nodes containing forms, named node maps, document fragments, or shadow DOM.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped3.4.6
Upgrade DOMPurify to version 3.4.6 or later. No other configuration changes are required; the fix is included in the library update.
3.4.6
- Check current DOMPurify version in your project (npm list dompurify or yarn list dompurify)
- Update DOMPurify to version 3.4.6 or later using your package manager: npm install dompurify@^3.4.6 or yarn upgrade dompurify@^3.4.6
- Verify the new version is installed correctly
- Rebuild and test your application to ensure the sanitizer functions as expected
- Check for any deprecation warnings after upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-49458 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-49458 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data