CVEs / CVE-2021-4034
CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability
- Known exploited in the CISA KEV catalog since 27 Jun 2022
- high 7.8 CVSS 3.1 (NVD)
- EPSS 94.9% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
The Red Hat polkit pkexec utility contains an out-of-bounds read and write vulnerability that allows for privilege escalation with administrative rights.
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| n/a polkit | all | — |
Exploitation
| In CISA KEV since | 27 Jun 2022 |
|---|---|
| Due date for US federal agencies | 18 Jul 2022 |
| Used in ransomware campaigns | Known |
| Required action | Apply updates per vendor instructions. |
Severity
| CVSS 3.1 | 7.8 highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HScored by NVD |
|---|---|
| Weakness | CWE-787, CWE-125 |
References
- CVE-2021-4034 on NVD
- CVE-2021-4034 in the CISA KEV catalog
- CVE-2021-4034 on OSV
- 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.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
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-4034 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.