ApostropheCMS: Incomplete CVE-2026-53606: `meta http-equiv=refresh` `content` still ships `javascript:` / `data:` URLs

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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 configuration that allows meta refresh elements and their http-equiv and content attributes can retain unsafe script or redirect destinations embedded in the refresh content value. This issue is fixed in sanitize-html 2.18.0.

Source published

20 Oct 2026 17:11:20 UTC

Source modified

21 Oct 2026 15:53:24 UTC

Observed here

23 Oct 2026 15:48:27 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 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A: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 configuration that allows meta refresh elements and their http-equiv and content attributes can retain unsafe script or redirect destinations embedded in the refresh content value. This issue is fixed in sanitize-html 2.18.0.

Source published

Oct 20, 2026, 5:11:20 PM (timezone not stated)

Source modified

Oct 21, 2026, 3:53:24 PM (timezone not stated)

Observed here

7 Nov 2026 04:34:27 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 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A: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 configuration that allows meta refresh elements and their http-equiv and content attributes can retain unsafe script or redirect destinations embedded in the refresh content value. This issue is fixed in sanitize-html 2.18.0.

Source published

20 Oct 2026 18:17:19 UTC

Source modified

21 Oct 2026 16:17:24 UTC

Observed here

25 Oct 2026 05:17:18 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 3.1 · [email protected] · Secondary · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

### Summary 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**: ```text 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 `[email protected]`. Output inspection only: ```text 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.

Source published

20 Oct 2026 18:15:33 UTC

Source modified

20 Oct 2026 18:30:03 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_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Publisher rating · MODERATE