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Vulnerabilities

Vulnerability · CVE-2021-4034

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

Published Jan 28, 2022 · catalog updated Aug 14, 2026 · Red Hat Polkit

Patch now

CVE-2021-4034 is in the CISA known-exploited catalog, due Jul 18, 2022. Confirm Red Hat Polkit against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
High7.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
94.92%
Remediation
Remediation guidance
Affected products
cpe canonical/ubuntu linux · cpe oracle/http server · cpe polkit project/polkit · cpe redhat/enterprise linux · cpe redhat/enterprise linux desktop · cpe redhat/enterprise linux eus

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe canonical/ubuntu linux14.04
  • cpe oracle/http server12.2.1.3.0
  • cpe polkit project/polkitversion unspecified
  • cpe redhat/enterprise linux8.0
  • cpe redhat/enterprise linux desktop7.0
  • cpe redhat/enterprise linux eus8.2
  • cpe redhat/enterprise linux for ibm z systems7.0
  • cpe redhat/enterprise linux for ibm z systems8.0
  • cpe redhat/enterprise linux server update services for sap solutions7.6
  • cpe redhat/enterprise linux server update services for sap solutions7.7
  • cpe siemens/sinumerik edgeversion unspecified
  • cpe suse/enterprise storage7.0
  • vendor Red Hat Polkitversion unspecified

How to fix CVE-2021-4034

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-4034 is in the CISA known-exploited catalog, due Jul 18, 2022. Confirm Red Hat Polkit against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with canonical/ubuntu linux 14.04; oracle/http server 12.2.1.3.0; redhat/enterprise linux 8.0; redhat/enterprise linux desktop 7.0. Apply updates per vendor instructions.

What should an analyst verify?

CWE-125: Out-of-bounds Read; CWE-787: Out-of-bounds Write. EPSS 94.92%. The CISA KEV listing is the exploitation evidence. A public exploit reference is linked in Sources. That is not the same as confirmed exploitation. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 28, 2022 · Catalog

    Detected

    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

  2. Jun 27, 2022 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Jul 18, 2022 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Aug 14, 2026 · Catalog

    Updated

    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

Sources

  • CISA KEVConfirmed exploitationCVE-2021-4034

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

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-4034

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-4034

    30-day exploitation probability 94.9%

    first.org
  • Exploit DatabasePublic exploit reference50689

    Public archive entry. The exploit body is not stored here.

    exploit-db.com
  • Metasploit ModulesPublic exploit moduleexploit_linux/local/cve_2021_4034_pwnkit_lpe_pkexec

    Public module reference (excellent). Module source is not copied into this catalog.

    rapid7.com
  • NIST NVDVulnerability recordCVE-2021-4034

    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 callin

    nvd.nist.gov
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/166196/Polkit-pkexec-Local-Privilege-Escalation.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • Packet Storm SecurityCited referencehttp://packetstormsecurity.com/files/166200/Polkit-pkexec-Privilege-Escalation.html

    Packet Storm link already published on the finding.

    packetstormsecurity.com
  • VulnCheck KEVConfirmed exploitationCVE-2021-4034

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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.