When reusing existing popups Firefox would have allowed them to cover the fullscreen notification UI, which could have enabled browser spoofing attacks. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.

A select option could partially obscure the confirmation prompt shown before launching external apps. This could be used to trick a user in to launching an external app unexpectedly. *This issue only affects Android versions of Firefox.* This vulnerability affects Firefox < 136.

The z-order of the browser windows could be manipulated to hide the fullscreen notification. This could potentially be leveraged to perform a spoofing attack. This vulnerability affects Firefox < 135 and Thunderbird < 135.

The fullscreen notification is prematurely hidden when fullscreen is re-requested quickly by the user. This could have been leveraged to perform a potential spoofing attack. This vulnerability affects Firefox < 135 and Thunderbird < 135.

A missing delay in directory upload UI could have made it possible for an attacker to trick a user into granting permission via clickjacking. This vulnerability affects Firefox < 131, Firefox ESR < 128.3, Thunderbird < 128.3, and Thunderbird < 131.

A select option could partially obscure security prompts. This could be used by a malicious site to trick a user into granting permissions. *This issue only affects Android versions of Firefox.* This vulnerability affects Firefox < 129.

Select options could obscure the fullscreen notification dialog. This could be used by a malicious site to perform a spoofing attack. This vulnerability affects Firefox < 129, Firefox ESR < 128.1, and Thunderbird < 128.1.

Under certain circumstances, navigating to a webpage would result in the address missing from the location URL bar, making it unclear what the URL was for the loaded webpage. This vulnerability affects Firefox for iOS < 133.

When the RSS Feed preview about:feeds page is framed within another page, it can be used in concert with scripted content for a clickjacking attack that confuses users into downloading and executing an executable file from a temporary directory. *Note: This issue only affects Windows operating systems. Other operating systems are not affected.*. This vulnerability affects Firefox < 64.

Multiple prompts and panels from both Firefox and the Android OS could be used to obscure the notification announcing the transition to fullscreen mode after the fix for CVE-2023-6870 in Firefox 121. This could lead to spoofing the browser UI if the sudden appearance of the prompt distracted the user from noticing the visual transition happening behind the prompt. These notifications now use the Android Toast feature. *This bug only affects Firefox on Android. Other operating systems are unaffected.* This vulnerability affects Firefox < 130.

By displaying a form validity message in the correct location at the same time as a permission prompt (such as for geolocation), the validity message could have obscured the prompt, resulting in the user potentially being tricked into granting the permission. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

By manipulating the fullscreen feature while opening a data-list, an attacker could have overlaid a text box over the address bar. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 127.

An improper implementation of the new iframe sandbox keyword <code>allow-top-navigation-by-user-activation</code> could lead to script execution without <code>allow-scripts</code> being present. This vulnerability affects Thunderbird < 91.9, Firefox ESR < 91.9, and Firefox < 100.