Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass. This vulnerability affects Firefox < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.
848478.678.6Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:HI:HA:H8.8/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H