VulnTideExploited vulnerabilities, by vendor. Data as of .
Known exploitedIn CISA's KEV catalog since Ransomware use: known
Red Hat Polkit

CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability

Also known as PwnKit

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 150 days after the CVE record was published.

How likely is exploitation in the next 30 days?
94.9%

EPSS score, percentile 99.9 of all scored records

How severe?
7.8 High

CVSS v3.1 base score, from CISA's enrichment of the record

What should I do?

CISA deadline . Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • all

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: .

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

n/a polkit
StatusVersions
Affectedall

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

About this vulnerability

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

Summary: CISA's KEV catalog, as of .

  • CISA added CVE-2021-4034 to its Known Exploited Vulnerabilities (KEV) catalog on 27 Jun 2022.
  • It is widely known as PwnKit, a common name that is not used in the CVE record or in CISA's catalog.
  • CISA marks it as known to be used in ransomware campaigns.
  • The due date CISA sets for the required action is 18 Jul 2022.
  • The CVE record was published on 28 Jan 2022, 150 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 7.8 (High), taken from CISA's enrichment of the record.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 94.9% (percentile 99.9), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
CVE record published
Added to CISA KEV
CISA due date for the required action
CVE record last updated

References

More exploited Red Hat vulnerabilities

  • CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability (added )
  • CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability (added )
  • CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability (added )
  • CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability (added )
  • CVE-2010-0738: Red Hat JBoss Authentication Bypass Vulnerability (added )
  • CVE-2010-1428: Red Hat JBoss Information Disclosure Vulnerability (added )