GHSA-CV27-6WVH-8X7J
Vulnerability from github – Published: 2026-10-20 18:15 – Updated: 2026-10-20 18:15Summary
CVE-2026-53606 expanded allowedSchemesAppliedToAttributes so named URL attributes (action, formaction, data, poster, background, later ping, xlink:href, …) go through naughtyHref(). A URL nested inside meta content (http-equiv=refresh) is not an attribute name on that list, so the embedded destination is never scheme-checked.
Default allowedTags still omit meta. Same non-default integrator config as 53606: allow meta plus http-equiv / content.
On 2.17.7:
sanitizeHtml(
'<meta http-equiv="refresh" content="0;url=javascript:alert(1)">',
{ allowedTags: ['meta'], allowedAttributes: { meta: ['http-equiv', 'content'] } }
)
// => <meta http-equiv="refresh" content="0;url=javascript:alert(1)" />
data:text/html,… and arbitrary https: destinations also survive. formaction="javascript:…" (53606) is stripped.
Please Request CVE. Credit: Finder + Reporter (adrbogacz).
Details
naughtyHref() only runs when the attribute name is in allowedSchemesAppliedToAttributes (index.js ~385). Refresh URLs live in a content value of the form 0;url=…, so the gate never fires. Adding content to that list wholesale would break ordinary meta content (description, viewport).
Fix: when http-equiv is refresh (case-insensitive), parse the ; url= destination and run naughtyHref('meta', url). Drop content (or the tag) if the URL is rejected. Leave other meta content values alone.
PoC
Local sanitize-html@2.17.7. Output inspection only:
node -e '
const sanitize = require("sanitize-html");
const opts = { allowedTags: ["meta"], allowedAttributes: { meta: ["http-equiv", "content"] } };
for (const html of [
"<meta http-equiv=\"refresh\" content=\"0;url=javascript:alert(1)\">",
"<meta http-equiv=\"refresh\" content=\"0;url=data:text/html,aaa\">",
"<form><button formaction=\"javascript:alert(1)\">x</button></form>",
]) {
console.log(html, "=>", sanitize(html, html.includes("meta") ? opts : { allowedTags: ["form","button"], allowedAttributes: { button: ["formaction"] } }));
}
'
Expected: refresh javascript: / data: remain; 53606 formaction is removed. Do not attach a browser hang or stored-XSS page.
Impact
An integrator who allowed meta + content expecting allowedSchemes to apply (the 53606 configuration pattern) still emits a refresh to javascript:, data:, or an attacker https: URL. Stored XSS / open redirect for viewers of that HTML. Default config is not affected.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "sanitize-html"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "2.18.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-113661"
],
"database_specific": {
"cwe_ids": [
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-20T18:15:33Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "### Summary\n\nCVE-2026-53606 expanded `allowedSchemesAppliedToAttributes` so named URL attributes (`action`, `formaction`, `data`, `poster`, `background`, later `ping`, `xlink:href`, \u2026) go through `naughtyHref()`. A **URL nested inside `meta` `content`** (`http-equiv=refresh`) is not an attribute name on that list, so the embedded destination is never scheme-checked.\n\nDefault `allowedTags` still omit `meta`. Same non-default integrator config as 53606: allow `meta` plus `http-equiv` / `content`.\n\nOn **2.17.7**:\n\n```text\nsanitizeHtml(\n \u0027\u003cmeta http-equiv=\"refresh\" content=\"0;url=javascript:alert(1)\"\u003e\u0027,\n { allowedTags: [\u0027meta\u0027], allowedAttributes: { meta: [\u0027http-equiv\u0027, \u0027content\u0027] } }\n)\n// =\u003e \u003cmeta http-equiv=\"refresh\" content=\"0;url=javascript:alert(1)\" /\u003e\n```\n\n`data:text/html,\u2026` and arbitrary `https:` destinations also survive. `formaction=\"javascript:\u2026\"` (53606) is stripped.\n\nPlease **Request CVE**. Credit: Finder + Reporter (`adrbogacz`).\n\n### Details\n\n`naughtyHref()` only runs when the attribute name is in `allowedSchemesAppliedToAttributes` (`index.js` ~385). Refresh URLs live in a `content` value of the form `0;url=\u2026`, so the gate never fires. Adding `content` to that list wholesale would break ordinary meta `content` (description, viewport).\n\n**Fix:** when `http-equiv` is `refresh` (case-insensitive), parse the `; url=` destination and run `naughtyHref(\u0027meta\u0027, url)`. Drop `content` (or the tag) if the URL is rejected. Leave other `meta` `content` values alone.\n\n### PoC\n\nLocal `sanitize-html@2.17.7`. Output inspection only:\n\n```text\nnode -e \u0027\nconst sanitize = require(\"sanitize-html\");\nconst opts = { allowedTags: [\"meta\"], allowedAttributes: { meta: [\"http-equiv\", \"content\"] } };\nfor (const html of [\n \"\u003cmeta http-equiv=\\\"refresh\\\" content=\\\"0;url=javascript:alert(1)\\\"\u003e\",\n \"\u003cmeta http-equiv=\\\"refresh\\\" content=\\\"0;url=data:text/html,aaa\\\"\u003e\",\n \"\u003cform\u003e\u003cbutton formaction=\\\"javascript:alert(1)\\\"\u003ex\u003c/button\u003e\u003c/form\u003e\",\n]) {\n console.log(html, \"=\u003e\", sanitize(html, html.includes(\"meta\") ? opts : { allowedTags: [\"form\",\"button\"], allowedAttributes: { button: [\"formaction\"] } }));\n}\n\u0027\n```\n\nExpected: refresh `javascript:` / `data:` remain; 53606 `formaction` is removed. Do not attach a browser hang or stored-XSS page.\n\n### Impact\n\nAn integrator who allowed `meta` + `content` expecting `allowedSchemes` to apply (the 53606 configuration pattern) still emits a refresh to `javascript:`, `data:`, or an attacker `https:` URL. Stored XSS / open redirect for viewers of that HTML. Default config is not affected.",
"id": "GHSA-cv27-6wvh-8x7j",
"modified": "2026-10-20T18:15:33Z",
"published": "2026-10-20T18:15:33Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-cv27-6wvh-8x7j"
},
{
"type": "WEB",
"url": "https://github.com/apostrophecms/apostrophe/commit/9500b8b0e1d630d5e07fbb5fd2c25ed0943845ce"
},
{
"type": "WEB",
"url": "https://github.com/apostrophecms/apostrophe/commit/f84fd41cbf6c22eb8d0008fc9c25df1f7130b350"
},
{
"type": "PACKAGE",
"url": "https://github.com/apostrophecms/apostrophe"
},
{
"type": "WEB",
"url": "https://github.com/apostrophecms/apostrophe/releases/tag/sanitize-html@2.18.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "ApostropheCMS: Incomplete CVE-2026-53606: `meta http-equiv=refresh` `content` still ships `javascript:` / `data:` URLs"
}
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