CVE-2026-33889

The record

ApostropheCMS is an open-source Node.js content management system. Versions 4.28.0 and prior contain a stored cross-site scripting vulnerability in the @apostrophecms/color-field module, where color values prefixed with -- bypass TinyColor validation intended for CSS custom properties, and the launder.string() call performs only type coercion without stripping HTML metacharacters. These unsanitized values are then concatenated directly into <style> tags both in per-widget style elements rendered for all visitors and in the global stylesheet rendered for editors, with the output marked as safe HTML. An editor can inject a value which closes the style tag and executes arbitrary JavaScript in the browser of every visitor to any page containing the affected widget. This enables mass session hijacking, cookie theft, and privilege escalation to administrative control if an admin views draft content. This issue has been fixed in version 4.29.0.

Affected packages

Related vulnerabilities

• GHSA-97v6-998m-fp4g ApostropheCMS: Stored XSS via CSS Custom Property Injection in @apostrophecms/color-field… Same vulnerability
• CVE-2026-45013 ApostropheCMS is an open-source Node.js content management system. Also affects apostrophe
• CVE-2026-45012 ApostropheCMS is an open-source Node.js content management system. Also affects apostrophe
• CVE-2026-45011 ApostropheCMS is an open-source Node.js content management system. Also affects apostrophe
• GHSA-5f64-7vfc-rcx6 Apostrophe has stored XSS via javascript: URL in Image Widget Link Also affects apostrophe
• GHSA-gf43-24g3-5hw2 Apostrophe has a Weak Password Recovery Mechanism for Forgotten Password and Improper… Also affects apostrophe
• GHSA-pr28-mf3q-qpg6 Apostrophe has authenticated SSRF in rich-text widget import via… Also affects apostrophe
• GHSA-c276-fj82-f2pq ApostropheCMS: Information Disclosure via choices/counts Query Parameters Bypassing… Also affects apostrophe