CVE-2021-4034

polkit

Published 28 Jan 2022 · updated 15 Aug 2026 · Analyzed

7.8 High · CVSS 3.1, NVD

Exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on 27 Jun 2022, with a remediation deadline of 18 Jul 2022 for US federal agencies. It has been used in ransomware campaigns.

Required action: Apply updates per vendor instructions.

Description

A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.

References