It was found that polkit could be tricked into bypassing the credential checks for D-Bus requests, elevating the privileges of the requestor to the root user. This flaw could be used by an unprivileged local attacker to, for example, create a new local administrator. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/
https://bugzilla.redhat.com/show_bug.cgi?id=1961710
http://packetstormsecurity.com/files/172846/Facebook-Fizz-Denial-Of-Service.html
http://packetstormsecurity.com/files/172836/polkit-Authentication-Bypass.html