A vulnerability in Polkit's pkexec component identified as CVE-2021-4034 (PwnKit) is present in the default configuration of all major Linux distributions and can be exploited to gain full root privileges on the system. Vulnerability is fixed in Ubuntu 21.10, 20.04 LTS and 18.04 LTS versions – ubuntu.com. Red Hat has also released security updates for Polkit component vulnerability - redhat.com.

Source: bleepingcomputer.com