Cantina_Security

The JSON:API and REST modules allow image file uploads to image fields. The validation rules verify the file extension but fail to check the file MIME type (Multipurpose Internet Mail Extensions), which is a standard used to identify the nature and format of a document. This flaw allows a malicious user to upload non-image files. Depending on the web-server configuration, these files may be served using their actual MIME type, potentially leading to cross-site scripting (XSS), where malicious scripts are injected into trusted websites, or other unexpected behavior.

Drupal core contains an issue where entity suggestions provided during the process of adding a link to CKEditor 5 are not sufficiently sanitized. This allows a malicious user to trigger a stored cross-site scripting (XSS) attack against other users. Cross-site scripting is a flaw where an application includes untrusted data in a web page without proper validation, allowing attackers to execute malicious scripts in the victim's browser.