CVE-2021-4034

HIGH
7.8
CVSS Score
Published: January 28, 2022 at 12:00 AM UTC
Updated: August 15, 2026 at 04:35 AM UTC
31 products affected across 7 vendorsUbuntu LinuxEnterprise LinuxEnterprise Linux Desktop

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Severity
HIGH7.8
Exploitation
CISA KEV
Exploit prediction
EPSS 95%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score94.9%

EPSS (Exploit Prediction Scoring System) estimates a 94.9% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

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

Required Action
Apply updates per vendor instructions.
Ransomware Use
Known
Added to KEV
Jun 27, 2022
Remediation Due
Jul 18, 2022
1561 days overdue

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHCISA-ADP
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-787CWE-125

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