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CVE-2021-4034

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This is a free service offered by Red Hot Cyber to the community. It allows you to view, on a single page, information about a single CVE from the National Vulnerability Database (NVD) and the National Institute of Standards and Technology (NIST) of the United States of America, the Forum of Incident Response and Security Teams (FIRST) regarding the EPSS score and percentile, data from the KEV catalog of the Cybersecurity and Infrastructure Security Agency (CISA), as well as selected resources from Red Hot Cyber and other international sources.

National Vulnerability Database Information

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 Base Score: 7.8 (v3.1)

The CVSS Base Score is a score from 0 to 10 that represents the intrinsic severity of a vulnerability. A higher score indicates greater severity.

Value
0.02.55.07.510.0
Published on: 01/28/2022 20:15:12
Last modified: 06/17/2026 04:18:55
NIST: CVE source from the National Vulnerability Database (NVD)

CVSS Metrics Details

  • Base Severity: HIGH
  • Vector String: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
  • Attack Vector: LOCAL
  • Attack Complexity: LOW
  • Privileges Required: LOW
  • User Interaction: NONE
  • Scope: UNCHANGED
  • Confidentiality Impact: HIGH
  • Integrity Impact: HIGH
  • Availability Impact: HIGH

Common Weakness Enumeration (CWE)

Database CWE: v4.18

CWE-787: Out-of-bounds Write ↗

The product writes data past the end, or before the beginning, of the intended buffer.

CWE-125: Out-of-bounds Read ↗

The product reads data past the end, or before the beginning, of the intended buffer.

Fonte: MITRE CWE


FIRST Information

EPSS Score: 0.9492

The EPSS (Exploit Prediction Scoring System) is a score from 0 to 1 that indicates the probability that a vulnerability will be exploited in the real world in the next 30 days. A higher value indicates a greater likelihood of exploitation.

Value
0.00.250.50.751.0

Percentile: 0.9985

The Percentile indicates how much higher this vulnerability's EPSS score is compared to all other vulnerabilities in the EPSS database. For example, a percentile of 0.90 (90%) means that 90% of vulnerabilities have an EPSS score equal to or lower than the current one.

Value
0.00.250.50.751.0

*Data updated as of: 2026-07-28


CISA Information (Known Exploited Vulnerabilities)

The CISA KEV Catalog lists vulnerabilities that have been actively exploited in the real world. If a CVE is present in this catalog, it indicates that the threat is immediate and mitigation should be a top priority.

CVE CVE-2021-4034 IS PRESENT in the CISA KEV Catalog!

  • Vulnerability Name: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability
  • Short Description: The Red Hat polkit pkexec utility contains an out-of-bounds read and write vulnerability that allows for privilege escalation with administrative rights.
  • Date Added to KEV: 06/27/2022
  • Vendor/Product: Red Hat / Polkit
  • Required Action: Apply updates per vendor instructions.
  • Due Date: 07/18/2022

Articles published on Red Hot Cyber


NVD References

Exploit PoC from GitHub