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.
By monitoring the time certain operations take, an attacker could have guessed which external protocol handlers were functional on a user's system. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.
By tricking the browser with a `X-Frame-Options` header, a sandboxed iframe could have presented a button that, if clicked by a user, would bypass restrictions to open a new window. This vulnerability affects Firefox < 127, Firefox ESR < 115.12, and Thunderbird < 115.12.