CVE-2021-4034

Name of the Vulnerable Software and Affected Versions polkit (affected versions not specified) policykit-1 versions prior to 0.105-25+deb10u1 policykit-1 versions prior to 0.105-31+deb11u1 policykit-1 versions prior to 0.105-4ubuntu3.14.04.6+esm1

Description A local privilege escalation issue exists in the pkexec utility of polkit. The pkexec application is a setuid tool that allows unprivileged users to execute commands as privileged users based on predefined policies. The utility fails to correctly handle the count of calling parameters, which can lead to an out-of-bounds write and cause the application to execute environment variables as commands. A local attacker can exploit this by crafting specific environment variables to induce pkexec to execute arbitrary code, granting the attacker administrative or root privileges on the target machine.

Recommendations Update policykit-1 to version 0.105-25+deb10u1 or later for the buster distribution. Update policykit-1 to version 0.105-31+deb11u1 or later for the bullseye distribution. Update policykit-1 to version 0.105-4ubuntu3.14.04.6+esm1 or later for Ubuntu 14.04 ESM and 16.04 ESM. As a temporary workaround, consider restricting access to the pkexec utility to minimize the risk of exploitation.