A stored Cross-site scripting (XSS) issue in Text Editors and Formats in Backdrop CMS before 1.24.2 allows remote attackers to inject arbitrary web script or HTML via the name parameter. When a user is editing any content type (e.g., page, post, or card) as an admin, the stored XSS payload is executed upon selecting a malicious text formatting option. NOTE: the vendor disputes the security relevance of this finding because "any administrator that can configure a text format could easily allow Full HTML anywhere."
Backdrop CMS 1.22.0 has Unrestricted File Upload vulnerability via 'themes' that allows attackers to Remote Code Execution. Note: Third parties dispute this and argue that advanced permissions are required.
An issue in the login and reset password functionality of Backdrop CMS v1.22.0 allows attackers to enumerate usernames via password reset requests and distinct responses returned based on usernames.