The executable file warning was not presented when downloading .inetloc files, which, due to a flaw in Mac OS, can run commands on a user's computer.*Note: This issue only affected Mac OS operating systems. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.
https://www.mozilla.org/security/advisories/mfsa2021-50/
https://www.mozilla.org/security/advisories/mfsa2021-49/