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DompurifyApplication · Cure53

CVE-2026-49459

MEDIUM · 6.1 CVSS v3.1 Published 2026-07-14
Fix available
A fix is available. Upgrade to 3.4.6 or later.
See remediation →
68/100
Remediation priority · Elevated
Public exploit Remotely reachable No privileges Patch available 5 weeks old

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 · unedited
DOMPurify is a DOM-only cross-site scripting sanitizer for HTML, MathML, and SVG. Prior to 3.4.6, DOMPurify.sanitize(root, { IN_PLACE: true }) could preserve event-handler attributes on an attacker-controlled <form> root when a descendant name clobbered properties checked by _isClobbered, because _forceRemove no-opped on the parent-less root and _sanitizeAttributes returned early. 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 confidence

DOMPurify before 3.4.6 fails to sanitize event-handler attributes on attacker-controlled `<form>` elements when using IN_PLACE mode. A name clobbering issue in the `_isClobbered` check causes `_forceRemove` to no-op on parent-less roots and `_sanitizeAttributes` to return early, allowing attributes like onclick to persist.

MitigationUpgrade DOMPurify to version 3.4.6 or later. Avoid using IN_PLACE mode with untrusted DOM roots until patched.

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
DompurifyApplication
Affected:< 3.4.6

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify DOMPurify usage in your codebase
    Search your codebase for imports or script tags referencing 'DOMPurify', 'dompurify', or the npm package 'dompurify'. Check package.json dependencies if using npm.
    Affected if DOMPurify is found in your project dependencies or loaded in your application.
  2. Determine the installed DOMPurify version
    If using npm, run 'npm list dompurify' or check package.json for the dompurify version entry. If loading via CDN or script tag, inspect the source file header for version information.
    Affected if The installed version is below 3.4.6.
  3. Locate code using IN_PLACE mode
    Search your codebase for patterns like 'DOMPurify.IN_PLACE', 'IN_PLACE: true', or 'DOMPurify.sanitize(..., { IN_PLACE: true })'. Review sanitization calls to see if this configuration option is set.
    Affected if IN_PLACE mode is enabled in any DOMPurify.sanitize() call.
  4. Verify if untrusted form elements are being processed
    Review the data sources passed to DOMPurify.sanitize() to determine if they could contain user-supplied or untrusted <form> elements. Check if the input originates from user input, external APIs, or database content that may include HTML form tags.
    Affected if Untrusted or user-controlled <form> elements are being sanitized by DOMPurify with IN_PLACE mode enabled.

Your environment is affected if DOMPurify version is below 3.4.6 AND you are using IN_PLACE mode to sanitize inputs that could contain attacker-controlled <form> elements with event-handler attributes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 3.4.6 or later
Fixed in 3.4.6
Vendor patch github.com →
Interim mitigation

Upgrade DOMPurify to version 3.4.6 or later. Avoid using IN_PLACE mode with untrusted DOM roots until patched.

Recommended fix High confidence

DOMPurify version 3.4.6

  1. 1. Identify the current version of DOMPurify in use by checking package.json or package-lock.json for the dompurify dependency
  2. 2. Upgrade DOMPurify to version 3.4.6 or later using a package manager (npm install [email protected] or yarn upgrade [email protected])
  3. 3. Rebuild and redeploy the application with the updated dependency
  4. 4. Test the application to verify the fix works and existing functionality is not broken, particularly any code using DOMPurify.sanitize() with IN_PLACE:true
Caveat Likely minimal; review DOMPurify 3.4.6 release notes for any breaking changes specific to your use case before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dompurify Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-49459 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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