A duplicate SystemPrincipal object could be created when parsing a non-system html document via DOMParser::ParseFromSafeString. This could have lead to bypassing web security checks. This vulnerability affects Firefox < 109.
109109Exploitability
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