A website could have obscured the fullscreen notification by using a URL with a scheme handled by an external program, such as a mailto URL. This could have led to user confusion and possible spoofing attacks. This vulnerability affects Firefox < 115, Firefox ESR < 102.13, and Thunderbird < 102.13.
115115102.13102.13Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:NI:HA:N6.5/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N