Through use of reportValidity() and window.open(), a plain-text validation message could have been overlaid on another origin, leading to possible user confusion and spoofing attacks. This vulnerability affects Firefox < 93, Thunderbird < 91.2, and Firefox ESR < 91.2.
939391.291.2Exploitability
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