Is CVE-2026-65904 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-65904 being exploited in the wild.

How severe is CVE-2026-65904?

Medium severity, with a CVSS score of 4.7, published 23 July 2026.

Is there a fix for CVE-2026-65904?

A patch was published on 2026-07-23: Version 3.4.4 listed as unaffected/patched in VulnCheck data Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-65904 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-65904?

Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-65904: cure53 DOMPurify XSS bypass in IN_PLACE mode via cross-realm nodes

CVE-2026-65904 · Severity: medium · CVSS 4.7 · Published 2026-07-23

DOMPurify is a popular library used to clean HTML and prevent malicious scripts from running in web applications. A flaw in its 'IN_PLACE' optimization mode allows malicious code to bypass security checks if the content comes from a different window or iframe. If an application uses this specific setting to process content from other frames, an attacker could execute unauthorized scripts (Cross-Site Scripting), potentially leading to data theft or account takeover.

Quick answers

Is CVE-2026-65904 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-65904 being exploited in the wild.
How severe is CVE-2026-65904?: Medium severity, with a CVSS score of 4.7, published 23 July 2026.
Which products and versions are affected?: cure53 DOMPurify <= 3.3.3.
Is there a fix for CVE-2026-65904?: A patch was published on 2026-07-23: Version 3.4.4 listed as unaffected/patched in VulnCheck data Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-65904 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-65904?: Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A vulnerability exists in DOMPurify's IN_PLACE sanitization mode due to an improper cross-realm check. The private _isNode() function utilizes an 'instanceof Node' check which fails when the provided element originates from a different window or realm (such as an iframe's contentDocument). When this check fails, DOMPurify incorrectly stringifies the element to '[object HTMLDivElement]', resets the IN_PLACE flag to false, and returns the original, unsanitized DOM node to the caller. An attacker can exploit this by providing a malicious element from a cross-window context, which will bypass all sanitization filters. While the vendor initially considered this an edge case, version 3.4.4 was later released to address the issue.

Affected products

cure53 DOMPurify <= 3.3.3

Timeline

2026-04-01: advisory: GHSA-4w3q-35jp-p934 published
2026-07-23: disclosed: CVE-2026-65904 published
2026-07-23: patched: Version 3.4.4 listed as unaffected/patched in VulnCheck data

References

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