Is CVE-2021-4034 being actively exploited?

Yes. CVE-2021-4034 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added on June 27, 2022.

What is the CVSS score for CVE-2021-4034?

CVE-2021-4034 has a CVSS 3.1 base score of 7.8 (HIGH).

CVE-2021-4034

HIGH · CVSS 7.8CISA KEV: actively exploitedEPSS 94.9%EU EUVD: exploited

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.

Key facts

CVSS score: 7.8 (v3.1)
Severity: HIGH
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-787
EPSS score: 94.9% (100th percentile)
In CISA KEV: Yes, added June 27, 2022
In EU EUVD: Yes (EUVD-2021-33934)
Published: January 28, 2022
NVD last modified: August 15, 2026
Status: Analyzed

CISA Known Exploited Vulnerability

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

Added to the KEV catalog on June 27, 2022; federal remediation due July 18, 2022. Known to be used in ransomware campaigns.

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2021-33934 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on August 15, 2026.

View on the EU Vulnerability Database

Affected products

canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
canonical / ubuntu linux
oracle / http server
oracle / http server
oracle / zfs storage appliance kit
polkit project / polkit
redhat / enterprise linux
redhat / enterprise linux desktop
redhat / enterprise linux eus
redhat / enterprise linux for ibm z systems
redhat / enterprise linux for ibm z systems
redhat / enterprise linux for ibm z systems eus
redhat / enterprise linux for ibm z systems eus
redhat / enterprise linux for power big endian
redhat / enterprise linux for power little endian
redhat / enterprise linux for power little endian
redhat / enterprise linux for power little endian eus
redhat / enterprise linux for power little endian eus
redhat / enterprise linux for power little endian eus
redhat / enterprise linux for scientific computing
redhat / enterprise linux server
redhat / enterprise linux server
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server aus
redhat / enterprise linux server eus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux server tus
redhat / enterprise linux server update services for sap solutions
redhat / enterprise linux server update services for sap solutions
redhat / enterprise linux server update services for sap solutions
redhat / enterprise linux server update services for sap solutions
redhat / enterprise linux server update services for sap solutions
redhat / enterprise linux workstation
siemens / scalance lpe9403
siemens / scalance lpe9403 firmware
siemens / sinumerik edge
starwindsoftware / command center
starwindsoftware / starwind virtual san
suse / enterprise storage
suse / linux enterprise desktop
suse / linux enterprise high performance computing

and 5 more…

Certified products that may be affected

28 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Red Hat Enterprise Linux 8 NSS Cryptographic Module - Red Hat, Inc. - FIPS 140 5513 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, LLC - FIPS 140 5461 - active
Red Hat Enterprise Linux 8 Kernel Cryptographic API - Red Hat, Inc. - FIPS 140 5089 - active
SUSE Linux Enterprise Server Version 15 SP2 - SUSE LLC - Common Criteria BSI-DSZ-CC-1168-2021 - active
Red Hat Enterprise Linux 8 OpenSSL Cryptographic Module - Red Hat®, Inc. - FIPS 140 4642 - historical

See all 28 in the Security Certifications Explorer.

References

http://packetstormsecurity.com/files/166196/Polkit-pkexec-Local-Privilege-Escalation.html(Exploit, Third Party Advisory, VDB Entry)
http://packetstormsecurity.com/files/166200/Polkit-pkexec-Privilege-Escalation.html(Third Party Advisory, VDB Entry)
https://access.redhat.com/security/vulnerabilities/RHSB-2022-001(Mitigation, Vendor Advisory)
https://bugzilla.redhat.com/show_bug.cgi?id=2025869(Issue Tracking, Patch)
https://cert-portal.siemens.com/productcert/pdf/ssa-330556.pdf(Third Party Advisory)
https://gitlab.freedesktop.org/polkit/polkit/-/commit/a2bf5c9c83b6ae46cbd5c779d3055bff81ded683(Patch)
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-4034(US Government Resource)
https://www.oracle.com/security-alerts/cpuapr2022.html(Patch, Third Party Advisory)
https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt(Exploit, Mitigation, Third Party Advisory)
https://www.secpod.com/blog/local-privilege-escalation-vulnerability-in-major-linux-distributions-cve-2021-4034/(Exploit, Third Party Advisory)
https://www.starwindsoftware.com/security/sw-20220818-0001/(Third Party Advisory)
https://www.suse.com/support/kb/doc/?id=000020564(Third Party Advisory)
https://www.vicarius.io/vsociety/posts/pwnkit-pkexec-lpe-cve-2021-4034(Exploit, Third Party Advisory)

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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