CVE-2026-58263

Jodit Editor: Mutation XSS in jodit clean-html via a MathML/style rawtext carrier

Stored XSS with no user interaction, in the default configuration, on the input paths that jodit's own clean-html is responsible for sanitizing. jodit's own test suite asserts this is a sanitization boundary: src/plugins/clean-html/clean-html.test.js asserts that editor.value = '<p>test <img src="" onerror="alert(111)" alt=""></p>' sanitizes to <p>test <img src="" alt=""></p> (the onerror removed) under the default config. The carrier in this report passes that same default-config sanitizer yet keeps the handler live, defeating the asserted guarantee. A prior fix in 4.12.21 addressed a stored XSS premised on an application re-rendering editor.value as trusted HTML, so this threat model is maintainer-acknowledged. Precondition: an attacker can place HTML into the editor (a content-submission role) and the editor output is later rendered. Any integration binding value to application state in jodit-react, loading a previously stored document, or inserting content via a plugin/button will execute attacker script in the victim's page.

Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.

CVE-2026-58263 has a CVSS score of 7.2 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.12.28); upgrading removes the vulnerable code path.

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Remove the gadget element at the source rather than re-sanitizing the output. A re-sanitize loop does not close this: nesting the carrier inside itself surfaces one level per parse, so one extra pass is bypassed at depth 2, and any fixed cap N is out-nested at depth N+2 (depth generalizes trivially). The robust fix is to drop any HTML-namespace element smuggled inside <math>/<svg> outside a spec integration point (<foreignObject>, <annotation-xml>, <desc>, <title>) during the element walk, the same approach DOMPurify's _checkValidNamespace uses. This is one pass and depth-independent. It must run on both entry points: the synchronous value-set safeHTML pass and the on-change walker (which does not call safeHTML). A regression test asserting that no on* survives a round-trip through editor.value, including the nested-carrier case, locks it in.

1. What is CVE-2026-58263? CVE-2026-58263 is a high-severity cross-site scripting (XSS) vulnerability in jodit (npm), affecting versions < 4.12.28. It is fixed in 4.12.28. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
2. How severe is CVE-2026-58263? CVE-2026-58263 has a CVSS score of 7.2 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of jodit are affected by CVE-2026-58263? jodit (npm) versions < 4.12.28 is affected.
4. Is there a fix for CVE-2026-58263? Yes. CVE-2026-58263 is fixed in 4.12.28. Upgrade to this version or later.
5. Is CVE-2026-58263 exploitable, and should I be worried? Whether CVE-2026-58263 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-58263 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-58263? Upgrade jodit to 4.12.28 or later.

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