CVE-2026-65913: Dompurify DOMPurify USE_PROFILES Prototype Pollution Allows Vulnerability

MODERATE
Advisory Identifier: GHSA-cj63-jhhr-wcxv
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CWE-1321
Published
Advisory Summary

CVE-2026-65913 is a MODERATE dompurify use_profiles prototype pollution allows vulnerability (CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) affecting Dompurify libraries in the npm ecosystem. The issue involves dompurify use_profiles prototype pollution allows event handlers. Remediation is available by upgrading affected packages to version 3.3.2.

CVE-2026-65913 at a Glance

CVE Identifier CVE-2026-65913
GHSA Identifier GHSA-cj63-jhhr-wcxv
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Product Dompurify
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-65913

To remediate this vulnerability, upgrade all affected Dompurify dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

dompurify fixed: 3.3.2 
npm install dompurify@3.3.2
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls dompurify

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-65913, inspect your project dependencies using npm:

npm ls dompurify

Analyze the terminal output to locate any version of Dompurify in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.3.2), your application is affected.

Note: The npm ls dompurify command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'), where the product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. In Dompurify, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Summary When `USE_PROFILES` is enabled, DOMPurify rebuilds `ALLOWED_ATTR` as a plain array before populating it with the requested allowlists. Because the sanitizer still looks up attributes via `ALLOWED_ATTR[lcName]`, any `Array.prototype` property that is polluted also counts as an allowlisted attribute. An attacker who can set `Array.prototype.onclick = true` (or a runtime already subject to prototype pollution) can thus force DOMPurify to keep event handlers such as `onclick` even when they are normally forbidden. The provided PoC sanitizes `<img onclick=...>` with `USE_PROFILES` and adds the sanitized output to the DOM; the polluted prototype allows the event handler to survive and execute, turning what should be a blocklist into a silent XSS vector. ## Impact Prototype pollution makes DOMPurify accept dangerous event handler attributes, which bypasses the sanitizer and results in DOM-based XSS once the sanitized markup is rendered. ## Credits Identified by Cantina’s Apex (https://www.cantina.security).

CVE-2026-65913 Affected Dompurify Versions

1 component(s)
Fixed Versions:
3.3.2
Product / Package Ecosystem Affected Versions Fixed Version
dompurify
npm/dompurify
npm
< 3.3.2
3.3.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/cure53/DOMPurify/security/advisories/GHSA-cj63-jhhr-wcxv
Dompurify Source Repository REPOSITORY
https://github.com/cure53/DOMPurify
Dompurify Release RELEASE
https://github.com/cure53/DOMPurify/releases/tag/3.3.2

Frequently Asked Questions

What is CVE-2026-65913?
CVE-2026-65913 is a security vulnerability in Dompurify involving DOMPurify USE_PROFILES prototype pollution allows event handlers under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution').
Which Dompurify versions are affected?
Affected versions include releases prior to 3.3.2 across affected packages: dompurify.
What version fixes CVE-2026-65913?
Upgrading to 3.3.2 (or the latest patched release for your respective branch) resolves the vulnerability.
Is dompurify affected?
Yes, dompurify is affected in releases prior to 3.3.2. Upgrade your dependency to 3.3.2 or later.
What CWE is associated with CVE-2026-65913?
CVE-2026-65913 is classified under CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.).
How can I check npm dependencies for CVE-2026-65913?
Run the dependency tree command: 'npm ls dompurify'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-cj63-jhhr-wcxv",
  "modified" : "2026-07-23T14:04:52Z",
  "published" : "2026-04-03T03:45:08Z",
  "aliases" : [ "CVE-2026-65913" ],
  "summary" : "DOMPurify USE_PROFILES prototype pollution allows event handlers",
  "details" : "## Summary\nWhen `USE_PROFILES` is enabled, DOMPurify rebuilds `ALLOWED_ATTR` as a plain array before populating it with the requested allowlists. Because the sanitizer still looks up attributes via `ALLOWED_ATTR[lcName]`, any `Array.prototype` property that is polluted also counts as an allowlisted attribute. An attacker who can set `Array.prototype.onclick = true` (or a runtime already subject to prototype pollution) can thus force DOMPurify to keep event handlers such as `onclick` even when they are normally forbidden. The provided PoC sanitizes `<img onclick=...>` with `USE_PROFILES` and adds the sanitized output to the DOM; the polluted prototype allows the event handler to survive and execute, turning what should be a blocklist into a silent XSS vector.\n\n## Impact\nPrototype pollution makes DOMPurify accept dangerous event handler attributes, which bypasses the sanitizer and results in DOM-based XSS once the sanitized markup is rendered.\n\n## Credits\nIdentified by Cantina’s Apex (https://www.cantina.security).",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "dompurify"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.3.2"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.3.1"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/cure53/DOMPurify/security/advisories/GHSA-cj63-jhhr-wcxv"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/cure53/DOMPurify"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/cure53/DOMPurify/releases/tag/3.3.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1321" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-03T03:45:08Z",
    "nvd_published_at" : null
  }
}