If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.
868678.878.8Exploitability
AV:NAC:LPR:NUI:RScope
S:UImpact
C:LI:NA:N4.3/CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N