CVE-2021-4023 : Security Advisory and Response

A flaw was discovered in the io-workqueue implementation in the Linux kernel versions prior to 5.15-rc1. This vulnerability can lead to a system crash when an improper operation triggers the submission of new io-uring operations during a shortage of free space, allowing a local user to exploit the system.

Understanding CVE-2021-4023

This section will provide insights into the impact, technical details, and mitigation strategies related to CVE-2021-4023.

What is CVE-2021-4023?

CVE-2021-4023 is a vulnerability in the Linux kernel that allows a local user to potentially crash the system by executing io-uring requests.

The Impact of CVE-2021-4023

The vulnerability in the io-workqueue implementation of the Linux kernel versions before 5.15-rc1 can result in a system panic when specific conditions are met, posing a risk of system instability.

Technical Details of CVE-2021-4023

In this section, we delve into the specifics of the vulnerability, including its description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The flaw in the io-workqueue implementation triggers a kernel panic when new io-uring operations are submitted during low free space, potentially exploited by a local user with appropriate permissions.

Affected Systems and Versions

The vulnerability impacts kernel versions earlier than 5.15-rc1, making systems running these versions susceptible to this issue.

Exploitation Mechanism

A local user with permission to execute io-uring requests can exploit this vulnerability to crash the system, leveraging the shortage of free space in io-workqueue operations.

Mitigation and Prevention

This section outlines immediate steps to mitigate the risk of exploitation and long-term security practices to enhance system resilience.

Immediate Steps to Take

System administrators are advised to monitor security updates, apply patches promptly, and restrict access to potentially vulnerable components to prevent unauthorized exploitation.

Long-Term Security Practices

Implementing least privilege access, enforcing security policies, and conducting regular security assessments can bolster the overall resilience of the system against potential vulnerabilities.

Patching and Updates

Regularly updating the Linux kernel to versions 5.15-rc1 and above is crucial to safeguard systems against CVE-2021-4023 and other known vulnerabilities.