CVE-2021-4034
Red Hat Polkit Out-of-Bounds Read and Write
- Published28 Jan 2022
- Added to CISA KEV27 Jun 2022
- Remediation due18 Jul 2022
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.
CVSS 3.1 breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HAffected products
Remediation
References
- http://packetstormsecurity.com/files/166196/Polkit-pkexec-Local-Privilege-Escalation.html
- http://packetstormsecurity.com/files/166200/Polkit-pkexec-Privilege-Escalation.html
- https://access.redhat.com/security/vulnerabilities/RHSB-2022-001
- https://bugzilla.redhat.com/show_bug.cgi?id=2025869
- https://cert-portal.siemens.com/productcert/pdf/ssa-330556.pdf
- https://gitlab.freedesktop.org/polkit/polkit/-/commit/a2bf5c9c83b6ae46cbd5c779d3055bff81ded683
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-4034
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt
- https://www.secpod.com/blog/local-privilege-escalation-vulnerability-in-major-linux-distributions-cve-2021-4034/
and 3 more references
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2021-4034 being actively exploited?
Yes. CVE-2021-4034 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 27 Jun 2022. It has been used in ransomware campaigns.
How severe is CVE-2021-4034?
CVE-2021-4034 has a CVSS 3.1 base score of 7.8, rated high. EPSS estimates a 94.3% probability of exploitation.
Which products are affected by CVE-2021-4034?
Affected products include Oracle HTTP Server, Oracle Zfs Storage Appliance Kit, Polkit, Redhat Enterprise Linux Server Update Services For Sap Solutions, Siemens Sinumerik Edge, and 19 more.
How do I fix CVE-2021-4034?
Upgrade affected software to a fixed version, for example Polkit 121, Siemens Sinumerik Edge 3.3.0, Siemens Scalance Lpe9403 Firmware 2.0 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2021-4034 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.