CVE-2025-25062: Backdropcms Backdrop CMS

Medium severity, CVSS 4.4. EPSS: 1.7% chance of exploitation in the next 30 days.

An XSS issue was discovered in Backdrop CMS 1.28.x before 1.28.5 and 1.29.x before 1.29.3. It doesn't sufficiently isolate long text content when the CKEditor 5 rich text editor is used. This allows a potential attacker to craft specialized HTML and JavaScript that may be executed when an administrator attempts to edit a piece of content. This vulnerability is mitigated by the fact that an attacker must have the ability to create long text content (such as through the node or comment forms) and an administrator must edit (not view) the content that contains the malicious content. This problem only exists when using the CKEditor 5 module.

Affected products

• Backdropcms Backdrop CMS: from 1.28.0, before 1.28.5 (fixed in 1.28.5); from 1.29.0, before 1.29.3 (fixed in 1.29.3)

Published 2025-02-03. Last modified 2026-06-17.