ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Prior to sanitize-html 2.18.0, a non-default nonTextTags configuration that includes noscript can end its discard region early when htmlparser2 emits an implied ancestor close inside noscript. Because scripting-enabled browsers treat noscript content as raw text while the parser does not model that mode, content intended to remain inert can survive sanitization and render; the issue does not generalize to every default nonTextTags element. This issue is fixed in sanitize-html 2.18.0.

Affected: npm: sanitize-html

## Summary

`sanitize-html` discards the *content* of every element in `nonTextTags`. It delimits that region using htmlparser2's close events, and ignores the `isImplied` flag htmlparser2 passes it. Closing a still-open **ancestor** from inside a `<noscript>` makes htmlparser2 unwind its stack past the `noscript`; the synthetic implied close it emits on the way ends the discard region early, and everything after it is treated as ordinary body content.

A browser with scripting enabled parses `<noscript>` content as **raw text**, so the same markup renders as inert text there. The sanitizer therefore emits elements the page itself would not have.

## Reproduction

```js const sanitizeHtml = require("sanitize-html");

sanitizeHtml('<div><noscript></div><img src="http://evil.test/t.gif"></noscript>', { allowedTags: ["div", "img"], allowedAttributes: { img: ["src"] }, nonTextTags: ["script", "style", "textarea", "option", "noscript"], }); // => '<div></div><img src="http://evil.test/t.gif" />' ```

Chrome, given the same input, renders **no** `<img>` — the whole payload is raw text inside the unclosed `<noscript>`. Verified with Playwright, `srcdoc` into an iframe so the scripting flag is on.

A `<![CDATA[` variant hides the opening tag from the parser entirely and has the same effect:

``` <p>Hi</p><![CDATA[ x > <noscript>]]><a href="…">Reset your password</a><img src="…beacon.gif"></noscript> ```

htmlparser2 runs a CDATA token to `]]>`; Chrome ends a bogus comment at t…