{"id":"CVE-2026-113654","aliases":["GHSA-x3q4-9hxx-gx8m"],"title":"ApostropheCMS sanitize-html: nonTextTags discard region ends early on an implied close, letting <noscript> content render","summary":"ApostropheCMS sanitize-html: nonTextTags discard region ends early on an implied close, letting <noscript> content render","severity":"medium","cvss":5.3,"cwe":["CWE-79"],"vendor":"sanitize-html","product":"sanitize-html","ecosystem":"npm","affected":["sanitize-html < 2.18.0"],"patched":["sanitize-html 2.18.0"],"published":"2026-10-20","updated":"2026-10-20","sourceUpdated":"2026-10-20T18:03:24Z","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-x3q4-9hxx-gx8m","references":[{"url":"https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-x3q4-9hxx-gx8m"},{"url":"https://github.com/apostrophecms/apostrophe/commit/9500b8b0e1d630d5e07fbb5fd2c25ed0943845ce"},{"url":"https://github.com/apostrophecms/apostrophe/commit/f84fd41cbf6c22eb8d0008fc9c25df1f7130b350"},{"url":"https://github.com/apostrophecms/apostrophe/releases/tag/sanitize-html@2.18.0"},{"url":"https://github.com/advisories/GHSA-x3q4-9hxx-gx8m"}],"tags":["ghsa","npm","cve.org"],"cvssVector":"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","cvssSource":"cna","ingestedAt":"2026-10-20T17:12:53.600Z","slug":"CVE-2026-113654","body":"## Overview\n\n## Summary\n\n`sanitize-html` discards the *content* of every element in `nonTextTags`. It delimits that region\nusing htmlparser2's close events, and ignores the `isImplied` flag htmlparser2 passes it. Closing a\nstill-open **ancestor** from inside a `<noscript>` makes htmlparser2 unwind its stack past the\n`noscript`; the synthetic implied close it emits on the way ends the discard region early, and\neverything after it is treated as ordinary body content.\n\nA browser with scripting enabled parses `<noscript>` content as **raw text**, so the same markup\nrenders as inert text there. The sanitizer therefore emits elements the page itself would not have.\n\n## Reproduction\n\n```js\nconst sanitizeHtml = require(\"sanitize-html\");\n\nsanitizeHtml('<div><noscript></div><img src=\"http://evil.test/t.gif\"></noscript>', {\n  allowedTags: [\"div\", \"img\"],\n  allowedAttributes: { img: [\"src\"] },\n  nonTextTags: [\"script\", \"style\", \"textarea\", \"option\", \"noscript\"],\n});\n// => '<div></div><img src=\"http://evil.test/t.gif\" />'\n```\n\nChrome, given the same input, renders **no** `<img>` — the whole payload is raw text inside the\nunclosed `<noscript>`. Verified with Playwright, `srcdoc` into an iframe so the scripting flag is on.\n\nA `<![CDATA[` variant hides the opening tag from the parser entirely and has the same effect:\n\n```\n<p>Hi</p><![CDATA[ x > <noscript>]]><a href=\"…\">Reset your password</a><img src=\"…beacon.gif\"></noscript>\n```\n\nhtmlparser2 runs a CDATA token to `]]>`; Chrome ends a bogus comment at the first `>`, so the\n`<noscript>` after it is real to the browser and invisible to the parser.\n\n## Where the behaviour is\n\n`index.js`:\n\n- `:154` — `nonTextTagsArray` (the default list, `['script','style','textarea','option','xmp']`).\n- `:638` — `onclosetag: function (name, isImplied)` — receives the flag.\n- `:644` — `skipTextDepth--` — decrements without consulting `isImplied`.\n\n## Suggested fix\n\nDo not end a discard region on an implied close. htmlparser2 already distinguishes them; the flag\nis passed and discarded. Something close to:\n\n```js\nonclosetag: function (name, isImplied) {\n  if (skipText) {\n    if (isImplied) return;   // an implied close must not end the region\n    skipTextDepth--;\n    …\n```\n\n## Affected packages\n\n- `sanitize-html < 2.18.0`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `sanitize-html 2.18.0`","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}