AIKIDO-2026-577091

TL;DR

The clean-html sanitizer's deny/allow tag filter in try-remove-node.ts compared node.nodeName against an upper-cased tag hash. Foreign (SVG/MathML) namespaced elements preserve their original-case node names, so an SVG script reports script instead of SCRIPT and slips past the default denyTags list. Attacker-supplied HTML such as <svg><script>...</script></svg> loaded into the editor is preserved in editor.value and serialized output, where it can execute when the stored content is rendered or reopened. The fix normalizes tag names to upper case before deny/allow lookups so foreign namespaces can no longer bypass the filter.