Jodit has cross-site scripting (XSS) via <script> nested in SVG that bypasses clean-html sanitization

A `<script>` element placed directly inside an `<svg>` (or MathML) container was not removed by Jodit's clean-html sanitizer. The deny/allow tag filter compared `node.nodeName` against an upper-cased tag hash, but foreign (SVG/MathML) elements preserve their original-case node names — an SVG script reports `"script"`, not `"SCRIPT"` — so the default `denyTags` list (which includes `script`) did not match it. The script therefore survived in the editor value and serialized output, where it could execute when the content was loaded back into a page or editor. ### Proof of concept ```html <svg xmlns="http://www.w3.org/2000/svg" width="400" height="400" viewBox="0 0 124 124"> <rect width="124" height="124" rx="24" fill="#000000"></rect> <script type="text/javascript">alert(document.domain);</script> </svg> ``` Load the payload into the editor (e.g. via source mode) and the `<script>` is preserved in `editor.value` and executes. ### Impact Stored / DOM cross-site scripting. An application that persists editor output and later renders or re-opens it in Jodit can have attacker-supplied script run in a victim's (e.g. an administrator's) authenticated browser context. ### Patch Fixed in **4.13.6**: the deny/allow lookup now normalises the tag name to upper case before matching, so a foreign namespace can no longer bypass the filter, while `allowTags` is still honoured. ### Workaround Upgrade to 4.13.6 or later. Server-side sanitization of stored HTML mitigates in the interim. ### Credit Reported by Roman Kis (@CrownKingClown).

Source published

31 Jul 2026 19:15:57 UTC

Source modified

31 Jul 2026 19:41:43 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

Publisher rating · MODERATE