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[ CVE-2021-4034 · Published 28 Jan 2022 ]

Red Hat Polkit Out-of-Bounds Read and Write Vulnerability

Exploited · CISA KEV CVSS 7.8 EPSS 95%Fix available

[ Why it matters ]Priority signals

  • Exploited in the wild: on CISA's Known Exploited Vulnerabilities list since 2022-06-27
  • Known to be used in ransomware campaigns
  • EPSS: 95% chance of exploitation in the next 30 days (higher than 100% of CVEs)

[ Description ]Official 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.

CISA: The Red Hat polkit pkexec utility contains an out-of-bounds read and write vulnerability that allows for privilege escalation with administrative rights.

[ Fixes ]Fixes and patches

CISA required action (US federal deadline 18 Jul 2022): Apply updates per vendor instructions.

[ References ]References