Cross-Site Request Forgery (CSRF) vulnerability via IMG element in Tiki before 16.3, 17.x before 17.1, 12 LTS before 12.12 LTS, and 15 LTS before 15.5 LTS allows an authenticated user to edit global permissions if an administrator opens a wiki page with an IMG element, related to tiki-objectpermissions.php. For example, an attacker could assign administrator privileges to every unauthenticated user of the site.