A website could have obscured the fullscreen notification by using an option element by introducing lag via an expensive computational function. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 115.
Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information across domains, or execute arbitrary code. Martin Hostettler discovered that Firefox did not properly block storage of all cookies when configured. An attacker could potentially exploits this issue to store tracking data without permission in localstorage.