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

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.

ApostropheCMS sanitize-html: unbounded recursion when re-sanitizing the fallback of a discarded iframe (stack overflow, nestingLimit not enforced)

ApostropheCMS is an open-source Node.js content management system. In sanitize-html 2.18.0, when an <iframe> is not allowed and disallowedTagsMode is 'discard' (the defaults), its raw-text content is re-sanitized by a recursive call to sanitizeHtml(text, options). The recursion has no bound and starts each nested call with a fresh state. This vulnerability is fixed in 2.18.1.

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

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.

ApostropheCMS sanitize-html: SMIL animation namespace-prefix bypass allows javascript: URI injection (XSS)

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. From sanitize-html 2.17.7 until 2.18.0, an application configuration that permits namespace-prefixed SVG animation elements and the relevant URL-targeting attributes can bypass the SMIL URL protection because prefixed tag names do not match the unprefixed animation-element check. The bypass can rewrite a link destination to an unsafe URI after the sanitized SVG is rendered, with script execution occurring when a user activates the affected link; the default sanitizer configuration is not unconditionally affected. This issue is fixed in sanitize-html 2.18.0.

Apostrophe has default XSS via `xmp` raw-text passthrough in `sanitize-html`

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Under the default configuration, versions of `sanitize-html` prior to 2.17.4 can turn attacker-controlled content inside a disallowed `xmp` element into live HTML or JavaScript. This is a sanitizer bypass in the default `disallowedTagsMode: 'discard'` path and can lead to stored XSS in applications that render sanitized output back to users. Version 2.17.4 patches the issue.

sanitize-html has an incomplete URI scheme validation that allows javascript: URIs through action, formaction, data, poster, and background attributes

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Versions of sanitize-html prior to 2.17.5 use `allowedSchemesAppliedToAttributes` (default: `['href', 'src', 'cite']`) to gate the `naughtyHref()` function that blocks dangerous URI schemes like `javascript:` and `vbscript:`. The HTML specification defines 10+ attributes that accept URIs (`action`, `formaction`, `data`, `poster`, `background`, `ping`, `xlink:href`, `dynsrc`, `lowsrc`), but none of these are included in the default gate list. When a developer allows any of these attributes in their configuration, `javascript:` URIs pass through completely unmodified, enabling XSS. Version 2.17.5 patches the issue.

ApostropheCMS: sanitize-html allowedTags Bypass via Entity-Decoded Text in nonTextTags Elements

ApostropheCMS is an open-source Node.js content management system. A regression introduced in commit 49d0bb7, included in versions 2.17.1 of the ApostropheCMS-maintained sanitize-html package bypasses allowedTags enforcement for text inside nonTextTagsArray elements (textarea and option). ApostropheCMS version 4.28.0 is affected through its dependency on the vulnerable sanitize-html version. The code at packages/sanitize-html/index.js:569-573 incorrectly assumes that htmlparser2 does not decode entities inside these elements and skips escaping, but htmlparser2 10.x does decode entities before passing text to the ontext callback. As a result, entity-encoded HTML is decoded by the parser and then written directly to the output as literal HTML characters, completely bypassing the allowedTags filter. An attacker can inject arbitrary tags including XSS payloads through any allowed option or textarea element using entity encoding. This affects non-default configurations where option or textarea are included in allowedTags, which is common in form builders and CMS platforms. This issue has been fixed in version 2.17.2 of sanitize-html and 4.29.0 of ApostropheCMS.

sanitize-html: sanitize-html cross site scripting

`sanitize-html` prior to version 2.0.0-beta is vulnerable to Cross-site Scripting (XSS). The `sanitizeHtml()` function in `index.js` does not sanitize content when using the custom `transformTags` option, which is intended to convert attribute values into text. As a result, malicious input can be transformed into executable code.

'sanitize-html' prior to version 1.0.3 is vulnerable to Cross-site Scripting (XSS). The function 'naughtyHref' doesn't properly validate the hyperreference (`href`) attribute in anchor tags (`<a>`), allowing bypasses that contain different casings, whitespace characters, or hexadecimal encodings.

sanitize-html: Information Exposure when used on the backend

Versions of the package sanitize-html before 2.12.1 are vulnerable to Information Exposure when used on the backend and with the style attribute allowed, allowing enumeration of files in the system (including project dependencies). An attacker could exploit this vulnerability to gather details about the file system structure and dependencies of the targeted server.

Regular Expression Denial of Service (ReDoS)

The package sanitize-html before 2.7.1 are vulnerable to Regular Expression Denial of Service (ReDoS) due to insecure global regular expression replacement logic of HTML comment removal.

sanitize-html: improper validation of hostnames set by the "allowedIframeHostnames" option can lead to bypass hostname whitelist for iframe element

Apostrophe Technologies sanitize-html before 2.3.2 does not properly validate the hostnames set by the "allowedIframeHostnames" option when the "allowIframeRelativeUrls" is set to true, which allows attackers to bypass hostname whitelist for iframe element, related using an src value that starts with "/\\example.com".

sanitize-html: improper handling of internationalized domain name (IDN) can lead to bypass hostname whitelist validation

Apostrophe Technologies sanitize-html before 2.3.1 does not properly handle internationalized domain name (IDN) which could allow an attacker to bypass hostname whitelist validation set by the "allowedIframeHostnames" option.

sanitize-html before 1.4.3 has XSS.