CVE-2023-6816 Explained : Impact and Mitigation

This CVE record highlights a heap buffer overflow vulnerability in the X.Org server, specifically in the devicefocusevent and procxiquerypointer components.

Understanding CVE-2023-6816

This section provides insights into the nature of the vulnerability, its impact, technical details, affected systems, and mitigation strategies.

What is CVE-2023-6816?

The flaw identified in the X.Org server involves the DeviceFocusEvent and the XIQueryPointer reply, which include a bit for each logical button currently pressed. Due to inadequate allocation of space in the X.Org Server, a heap overflow could occur if a larger value is used for button mapping.

The Impact of CVE-2023-6816

This vulnerability has a base severity rating of HIGH (7.8) according to the CVSS v3.1 metrics. It can result in high impacts on confidentiality, integrity, and availability of affected systems. The attack vector is local with low privileges required.

Technical Details of CVE-2023-6816

The vulnerability description involves the insufficient allocation of space for mapping logical buttons in the X.Org server, leading to a heap overflow. Affected systems include Red Hat Enterprise Linux versions 7, 8, and 9, as well as Fedora.

Vulnerability Description

The X.Org server fails to allocate adequate space for logical button mappings, potentially leading to a heap buffer overflow.

Affected Systems and Versions

Impacted products include xorg-server, xwayland, tigervnc on Red Hat Enterprise Linux 6, 7, 8, and 9, as well as Fedora.

Exploitation Mechanism

The vulnerability can be exploited by manipulating logical button mappings to trigger a heap overflow within the X.Org server.

Mitigation and Prevention

Protecting systems from CVE-2023-6816 requires immediate actions and long-term security practices.

Immediate Steps to Take

Stay informed about security updates from Red Hat for affected products.
Monitor vendor advisories for patches and mitigations.
Consider implementing temporary workarounds if available.

Long-Term Security Practices

Regularly update systems with the latest security patches.
Conduct vulnerability assessments and penetration testing.
Implement robust access controls and network segmentation to contain potential exploits.

Patching and Updates

Apply relevant patches provided by Red Hat for vulnerable products to address the heap buffer overflow vulnerability in the X.Org server components.

This vulnerability was responsibly reported to Red Hat by Jan-Niklas Sohn from Trend Micro Zero Day Initiative.