ApostropheCMS sanitize-html: nonTextTags discard region ends early on an implied close, letting <noscript> content render

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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.

Source published

20 Oct 2026 16:35:55 UTC

Source modified

28 Oct 2026 14:01:09 UTC

Observed here

28 Oct 2026 15:46:50 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

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.

Source published

Oct 20, 2026, 4:35:55 PM (timezone not stated)

Source modified

Oct 28, 2026, 2:01:09 PM (timezone not stated)

Observed here

30 Oct 2026 01:57:29 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

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.

Source published

20 Oct 2026 17:17:36 UTC

Source modified

28 Oct 2026 14:16:56 UTC

Observed here

29 Oct 2026 06:48:04 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

## 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 the first `>`, so the `<noscript>` after it is real to the browser and invisible to the parser. ## Where the behaviour is `index.js`: - `:154` — `nonTextTagsArray` (the default list, `['script','style','textarea','option','xmp']`). - `:638` — `onclosetag: function (name, isImplied)` — receives the flag. - `:644` — `skipTextDepth--` — decrements without consulting `isImplied`. ## Suggested fix Do not end a discard region on an implied close. htmlparser2 already distinguishes them; the flag is passed and discarded. Something close to: ```js onclosetag: function (name, isImplied) { if (skipText) { if (isImplied) return; // an implied close must not end the region skipTextDepth--; … ```

Source published

20 Oct 2026 18:03:22 UTC

Source modified

20 Oct 2026 18:15:04 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

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

Publisher rating · MODERATE