CVE-2021-26708 : Security Advisory and Response

A local privilege escalation vulnerability was discovered in the Linux kernel before version 5.10.13, specifically in the AF_VSOCK implementation due to multiple race conditions. This vulnerability arises from incorrect locking in net/vmw_vsock/af_vsock.c and was inadvertently introduced during the addition of VSOCK multi-transport support.

Understanding CVE-2021-26708

This section delves into the impact and technical details of CVE-2021-26708.

What is CVE-2021-26708?

CVE-2021-26708 is a local privilege escalation vulnerability found in the Linux kernel before version 5.10.13. It stems from race conditions in the AF_VSOCK implementation due to incorrect locking mechanisms.

The Impact of CVE-2021-26708

This vulnerability could allow a local attacker to escalate their privileges on the system, potentially leading to unauthorized access and control over the affected system.

Technical Details of CVE-2021-26708

Below are the technical aspects associated with CVE-2021-26708.

Vulnerability Description

The vulnerability in the AF_VSOCK implementation of the Linux kernel is a result of multiple race conditions, primarily caused by incorrect locking procedures in net/vmw_vsock/af_vsock.c.

Affected Systems and Versions

Systems running Linux kernel versions before 5.10.13 are affected by this privilege escalation vulnerability in the AF_VSOCK implementation.

Exploitation Mechanism

Attackers can exploit the race conditions present in the AF_VSOCK implementation to potentially escalate their privileges on the system and gain unauthorized access.

Mitigation and Prevention

Outlined below are the steps to mitigate and prevent exploitation of CVE-2021-26708.

Immediate Steps to Take

Users are advised to update their Linux kernels to version 5.10.13 or above to eliminate the vulnerability and prevent potential privilege escalation attacks.

Long-Term Security Practices

Implementing strong access controls, regularly monitoring system activity, and employing security best practices can enhance the overall security posture and help prevent similar vulnerabilities.

Patching and Updates

Regularly applying security patches and updates provided by the Linux kernel maintainers is crucial to address known vulnerabilities and enhance system security.