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.
Affected: npm: sanitize-html
## Summary
Commit 49d0bb7 introduced a regression in sanitize-html that bypasses `allowedTags` enforcement for text inside `nonTextTagsArray` elements (`textarea` and `option`). Entity-encoded HTML inside these elements passes through the sanitizer as decoded, unescaped HTML, allowing injection of arbitrary tags including XSS payloads. This affects any application using sanitize-html that includes `option` or `textarea` in its `allowedTags` configuration.
## Details
The vulnerable code is at `packages/sanitize-html/index.js:569-573`:
```javascript } else if ((options.disallowedTagsMode === 'discard' || options.disallowedTagsMode === 'completelyDiscard') && (nonTextTagsArray.indexOf(tag) !== -1)) { // htmlparser2 does not decode entities inside raw text elements like // textarea and option. The text is already properly encoded, so pass // it through without additional escaping to avoid double-encoding. result += text; } ```
The comment is factually incorrect. htmlparser2 10.x **does** decode HTML entities inside both `<textarea>` and `<option>` elements before passing text to the `ontext` callback. This can be verified:
```javascript const htmlparser2 = require('htmlparser2'); const parser = new htmlparser2.Parser({ ontext(text) { console.log(JSON.stringify(text)); } }); parser.write('<option><script></option>'); // Outputs: "<", "script", ">" — entities are decoded ```
Because the code assumes the text is "already properly encoded" and skips `escapeHt…
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM App Connect Enterprise ausnutzen, um beliebigen Programmcode auszuführen, Daten zu manipulieren, Cross-Site-Scripting-Angriffe durchzuführen, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.