Medium [CVE-2026-49458] Cross-site scripting due to improper sanitization of DOM nodes
This medium-severity Red Hat Linux advisory covers CVE-2026-49458 affecting Migration Toolkit for Virtualization, Node HealthCheck Operator, OpenShift Lightspeed.
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Summary
DOMPurify 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. When processing certain types of web page elements, DOMPurify failed to properly identify and sanitize malicious code.
This oversight could allow an attacker to inject and execute harmful scripts within a user's web browser, potentially leading to information disclosure or unauthorized actions.
This Moderate cross-site scripting (XSS) flaw in DOMPurify arises when the `DOMPurify.sanitize()` function is used with the `IN_PLACE: true` option on DOM nodes originating from a different realm (e.g., an iframe). This misconfiguration bypasses critical sanitization checks, allowing executable markup to persist.
Red Hat products utilizing DOMPurify in this specific manner could be vulnerable to information disclosure or unauthorized actions if processing untrusted content. Red Hat severity: Moderate — CVSS 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).
Weakness: CWE-79.
- < 3.4.6
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
Mitigation
Upgrade to a fixed release: 3.4.6. That is the remediation for this advisory.
The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.
Official advisory · high-confidence parse· fetched 6 days ago·verify at source
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