CVE-2021-26910 : What You Need to Know

Firejail before 0.9.64.4 has a vulnerability that allows attackers to bypass access restrictions due to a TOCTOU race condition between a stat operation and an OverlayFS mount operation.

Understanding CVE-2021-26910

This CVE refers to a security flaw in Firejail that enables attackers to circumvent access controls via a race condition.

What is CVE-2021-26910?

The CVE-2021-26910 vulnerability in Firejail allows malicious actors to evade intended access restrictions by exploiting a timing race condition.

The Impact of CVE-2021-26910

The impact of CVE-2021-26910 is rated as high, with a CVSS base score of 7.8, affecting confidentiality, integrity, and availability.

Technical Details of CVE-2021-26910

This section delves into the specifics of the vulnerability in Firejail.

Vulnerability Description

The vulnerability arises from the inadequate handling of access restrictions, leading to a race condition that can be exploited by attackers.

Affected Systems and Versions

Firejail versions prior to 0.9.64.4 are impacted by this vulnerability, allowing attackers to bypass intended restrictions.

Exploitation Mechanism

Attackers can exploit the TOCTOU race condition between a stat operation and an OverlayFS mount operation to escalate privileges locally.

Mitigation and Prevention

To protect your systems from CVE-2021-26910, certain steps need to be taken.

Immediate Steps to Take

Users are advised to update Firejail to version 0.9.64.4 or later to mitigate the vulnerability and enhance security.

Long-Term Security Practices

Implementing regular security updates and patches, along with robust access control mechanisms, can help prevent similar vulnerabilities.

Patching and Updates

Regularly check for updates from Firejail and apply patches promptly to address any new security issues.