Vulnerability report

Exploited in the wild Confirmed confidence In CISA KEV

CVE-2021-4034

polkit Privilege Escalation

Freedesktop.org / polkit · all

Watch CVE-2021-4034 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Exploited in the wild
EPSS
94.3%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2021-4034 is a vulnerability affecting Freedesktop.org polkit. A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow...

Is it exploited?

Yes. Previdian tracks this CVE as a known exploited vulnerability. Confidence is confirmed. Listed in CISA KEV. Also confirmed by third-party sources.

Who is affected?

Freedesktop.org / polkit all.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

A local privilege escalation vulnerability was found on polkit's pkexec utility

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.

n/a Affected
polkit
all
Published
28 Jan 2022
Exploitation Reported
27 Jun 2022
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

metasploit nessus_scanner cisa

CVE References

Exploitation evidence

Why Previdian marks this CVE as exploited

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploited in the wild

CISA

Recorded 27 Jun 2022

A trusted third party reported exploitation.

Proof of concept available

GitHub

Recorded 25 Jan 2022

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CISA First 2022-06-27 00:00 UTC
CVE 2026-08-15 04:10 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
0
0
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/cve_2021_4034_pwnkit_lpe_pkexec.rb 28 Apr 2025

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

94.3%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Out-of-bounds Write CWE-787

Recent mention · The Hacker News

CyberXero Uses Claude Code in Campaign That Stole Over 628,000 Ukrainian Records

Ravie LakshmananOct 12, 2026Web Security / Cybercrime Cybersecurity researchers have disclosed details of a two-pronged artificial intelligence (AI)-augmented initial access campaign targeting WordPress sites, e-commerce platforms, and critical infrastructure entities in...

Read full advisory

All CVSS Scores

CVSS v3.1 7.8 High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v2.0 7.2 High

AV:L/AC:L/Au:N/C:C/I:C/A:C

All Mentions

Recent mention · The Hacker News

CyberXero Uses Claude Code in Campaign That Stole Over 628,000 Ukrainian Records

The Hacker News · 12 Oct 2026

Ravie LakshmananOct 12, 2026Web Security / Cybercrime Cybersecurity researchers have disclosed details of a two-pronged artificial intelligence (AI)-augmented initial access campaign targeting WordPress sites, e-commerce platforms, and critical infrastructure entities in Ukraine. The activity, which brings together commodity offensive tools like Cobalt Strike with an AI orchestration layer powered by Anthropic's Claude Code, has been attributed to a Russian-speaking, financially motivated initial access broker codenamed CyberXero. The threat actor is assessed to be active since at least...

Recent mention · SOCRadar

Operation Master: Deconstructing a Multi-Tiered Intrusion and Monetization Pipeline

SOCRadar · 24 Sep 2026

Operation Master: Deconstructing a Multi-Tiered Intrusion and Monetization Pipeline SOCRadar Threat Research Unit (STRU) has uncovered an end-to-end cybercrime operation dubbed Operation Master, in which a threat actor c

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

Rvn0xsy/CVE-2021-4034

github · Created 2022-01-28 15:13:28 UTC · 97 stars · AI assessment 90%

CVE-2021-4034 Add Root User - Pkexec Local Privilege Escalation

EstamelGG/CVE-2021-4034-NoGCC

github · Created 2022-01-28 02:54:38 UTC · 79 stars · AI assessment 90%

CVE-2021-4034简单优化，以应对没有安装gcc和make的目标环境

c3c/CVE-2021-4034

github · Created 2022-01-27 17:43:24 UTC · 25 stars · AI assessment 85%

Pre-compiled builds for CVE-2021-4034

PwnFunction/CVE-2021-4034

github · Created 2022-01-27 14:43:57 UTC · 344 stars · AI assessment 90%

Proof of concept for pwnkit vulnerability

joeammond/CVE-2021-4034

github · Created 2022-01-26 17:53:16 UTC · 165 stars · AI assessment 90%

Python exploit code for CVE-2021-4034 (pwnkit)

zhzyker/CVE-2021-4034

github · Created 2022-01-26 07:19:21 UTC · 45 stars · AI assessment 90%

polkit pkexec Local Privilege Vulnerability to Add custom commands

Ayrx/CVE-2021-4034

github · Created 2022-01-26 03:33:47 UTC · 93 stars · AI assessment 90%

Exploit for CVE-2021-4034

nikaiw/CVE-2021-4034

github · Created 2022-01-26 02:02:25 UTC · 62 stars · AI assessment 90%

PoC for CVE-2021-4034

arthepsy/CVE-2021-4034

github · Created 2022-01-26 00:56:36 UTC · 1078 stars · AI assessment 90%

PoC for PwnKit: Local Privilege Escalation Vulnerability in polkit’s pkexec (CVE-2021-4034)

berdav/CVE-2021-4034

github · Created 2022-01-25 23:51:37 UTC · 1990 stars · AI assessment 90%

CVE-2021-4034 1day

ryaagard/CVE-2021-4034

github · Created 2022-01-25 23:11:30 UTC · 72 stars · AI assessment 90%

Local Privilege Escalation in polkit's pkexec

cve_2021_4034_pwnkit_lpe_pkexec

metasploit · Created Unknown

Metasploit module for CVE-2021-4034

Timeline

From disclosure to observed exploitation

  1. 04:10 UTC

    KEV confirmed by CVE

    Exploitation attested by an external source

  2. 15:02 UTC

    Metasploit module available

    Exploit module available

  3. 00:00 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  4. 00:00 UTC

    CVE published

    Vulnerability disclosed publicly

  5. 23:11 UTC

    Public PoC available

    Public proof-of-concept code published

  6. 00:00 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2021-4034

Free JSON includes basic KEV fields 
{
  "cve_id": "CVE-2021-4034",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.94345,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}