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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-41239

MEDIUM · 6.8 CVSS v3.1 Published 2026-04-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
75/100
Remediation priority · High
Remotely reachable No privileges

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. Starting in version 1.0.10 and prior to version 3.4.0, `SAFE_FOR_TEMPLATES` strips `{{...}}` expressions from untrusted HTML. This works in string mode but not with `RETURN_DOM` or `RETURN_DOM_FRAGMENT`, allowing XSS via template-evaluating frameworks like Vue 2. Version 3.4.0 patches the issue.

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 · moderate confidence

DOMPurify's SAFE_FOR_TEMPLATES feature, designed to strip {{...}} template expressions from untrusted HTML to prevent XSS in frameworks like Vue 2, fails to properly sanitize content when using RETURN_DOM or RETURN_DOM_FRAGMENT modes. While string-mode sanitization correctly removes template expressions, the DOM return modes pass through unsanitized {{...}} strings, enabling XSS in applications using template-evaluating frameworks.

MitigationUpgrade DOMPurify to version 3.4.0 or later to patch this vulnerability. Review all code paths using RETURN_DOM or RETURN_DOM_FRAGMENT modes with SAFE_FOR_TEMPLATES enabled to confirm proper sanitization after upgrading.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
High
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/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 version
    Check your package.json, npm list dompurify, or the script tag version to determine the installed DOMPurify version
    Affected if The version is below 3.4.0, meaning the patch is not applied
  2. Verify SAFE_FOR_TEMPLATES configuration
    Search your codebase for DOMPurify configurations using SAFE_FOR_TEMPLATES: true or SAFE_FOR_TEMPLATES enabled in the options object
    Affected if SAFE_FOR_TEMPLATES is explicitly enabled in your DOMPurify configuration
  3. Check for RETURN_DOM or RETURN_DOM_FRAGMENT usage
    Search your codebase for DOMPurify calls using RETURN_DOM or RETURN_DOM_FRAGMENT in the configuration options
    Affected if Either RETURN_DOM or RETURN_DOM_FRAGMENT mode is being used with the sanitization call
  4. Confirm template framework usage
    Identify if your application uses template-evaluating frameworks like Vue 2, Angular, or similar that process {{...}} expressions
    Affected if The sanitized output is rendered or processed by a framework that evaluates double-curly template expressions
  5. Test for unsanitized template expressions
    Run DOMPurify with SAFE_FOR_TEMPLATES and RETURN_DOM/RETURN_DOM_FRAGMENT on input containing {{alert(1)}} and inspect if the expression remains in the output
    Affected if The {{...}} expression passes through unsanitized when using DOM return modes despite SAFE_FOR_TEMPLATES being enabled

You are affected if you use DOMPurify version below 3.4.0 with SAFE_FOR_TEMPLATES enabled alongside RETURN_DOM or RETURN_DOM_FRAGMENT, and the output feeds into a template-evaluating framework.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade DOMPurify to version 3.4.0 or later to patch this vulnerability. Review all code paths using RETURN_DOM or RETURN_DOM_FRAGMENT modes with SAFE_FOR_TEMPLATES enabled to confirm proper sanitization after upgrading.

Recommended fix High confidence

DOMPurify version 3.4.0 or later

  1. 1. Identify the current version of DOMPurify in your project by checking package.json or your package lock file.
  2. 2. If your current version is 1.0.10 or later but earlier than 3.4.0, upgrade to version 3.4.0 or later.
  3. 3. Run your package manager update command (e.g., npm install [email protected], yarn upgrade [email protected], or pip install --upgrade dompurify depending on your integration).
  4. 4. Test your application to verify that the SAFE_FOR_TEMPLATES option now properly sanitizes template expressions when using RETURN_DOM or RETURN_DOM_FRAGMENT modes.
Caveat Review release notes for 3.4.0 to check for any API changes that might affect your implementation; minor version bumps typically maintain backward compatibility

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

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,340
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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-2026-41239 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