Through complicated navigations with new windows, an HTTP page could have inherited a secure lock icon from an HTTPS page. This vulnerability affects Firefox ESR < 78.10, Thunderbird < 78.10, and Firefox < 88.Referenceshttps://www.mozilla.org/security/advisories/mfsa2021-14/https://www.mozilla.org/security/advisories/mfsa2021-16/https://www.mozilla.org/security/advisories/mfsa2021-15/https://bugzilla.mozilla.org/show_bug.cgi?id=1667456
