A host header attack vulnerability exists in FUEL CMS 1.5.0 through fuel/modules/fuel/config/fuel_constants.php and fuel/modules/fuel/libraries/Asset.php. An attacker can use a man in the middle attack such as phishing.
An issue was discovered in FUEL CMS 1.4.7. There is a escalation of privilege vulnerability to obtain super admin privilege via the "id" and "fuel_id" parameters.
In FUEL CMS 11.4.12 and before, the page preview feature allows an anonymous user to take complete ownership of any account including an administrator one.