CVE-2023-6683 : Security Advisory and Response

This CVE record was assigned by Red Hat and published on January 12, 2024. The vulnerability is related to a null pointer dereference in the qemu_clipboard_request() function within the QEMU built-in VNC server.

Understanding CVE-2023-6683

This section explains the impact, technical details, affected systems, and mitigation strategies for CVE-2023-6683.

What is CVE-2023-6683?

CVE-2023-6683 is a vulnerability in the QEMU built-in VNC server that allows a malicious authenticated VNC client to crash QEMU, leading to a denial of service. The issue arises due to a flaw in processing ClientCutText messages, resulting in a NULL pointer dereference.

The Impact of CVE-2023-6683

The impact of CVE-2023-6683 is rated as moderate. It has the potential to cause a denial of service if exploited by a malicious authenticated VNC client. The vulnerability affects certain versions of Red Hat Enterprise Linux, Fedora, and QEMU products.

Technical Details of CVE-2023-6683

The technical details of this vulnerability include a null pointer dereference in the qemu_clipboard_request() function, which can be triggered by processing ClientCutText messages in the QEMU built-in VNC server.

Vulnerability Description

The vulnerability in QEMU's VNC server allows an authenticated VNC client to crash QEMU by exploiting a NULL pointer dereference, resulting in a denial of service.

Affected Systems and Versions

The affected systems include Red Hat Enterprise Linux versions 6, 7, 8, 9, Fedora, and specific QEMU products related to these operating systems.

Exploitation Mechanism

An attacker with authenticated access to the VNC server can exploit this vulnerability by sending specially crafted ClientCutText messages, leading to a NULL pointer dereference and denial of service.

Mitigation and Prevention

To address CVE-2023-6683, it is important to take immediate steps, implement long-term security practices, and apply relevant patches and updates.

Immediate Steps to Take

Given that mitigation options may not meet Red Hat's security criteria, it is crucial to monitor for security advisories and updates from Red Hat or respective vendors for any available fixes or workarounds.

Long-Term Security Practices

Maintain vigilance over network access and authentication mechanisms to prevent unauthorized access and reduce the risks associated with potential vulnerabilities like CVE-2023-6683.

Patching and Updates

Stay informed about patches and security updates released by Red Hat, Fedora, and QEMU to address CVE-2023-6683. Regularly apply updates to ensure system security and protect against known vulnerabilities.

This comprehensive overview provides insights into the impact, technical aspects, affected systems, and mitigation strategies for CVE-2023-6683 related to the null pointer dereference in the QEMU VNC server.