CVE-2021-3638 : Security Advisory and Response

An out-of-bounds memory access flaw was found in the ATI VGA device emulation of QEMU, affecting versions 4.0 to 6.1. This vulnerability allows a malicious guest to crash the QEMU process, leading to a denial of service.

Understanding CVE-2021-3638

This section will cover what CVE-2021-3638 is and its impact.

What is CVE-2021-3638?

The CVE-2021-3638 is an out-of-bounds memory access flaw in the ATI VGA device emulation of QEMU. The flaw occurs in the ati_2d_blt() routine when handling MMIO write operations with invalid values for the destination display parameters.

The Impact of CVE-2021-3638

A malicious guest can exploit this flaw to crash the QEMU process on the host system, causing a denial of service.

Technical Details of CVE-2021-3638

Let's delve into the vulnerability description, affected systems, and exploitation mechanism.

Vulnerability Description

The flaw arises due to improper handling of MMIO write operations in the ati_2d_blt() routine within QEMU's ATI VGA device emulation.

Affected Systems and Versions

The vulnerability affects QEMU versions 4.0 to 6.1.

Exploitation Mechanism

By providing invalid values for destination display parameters, a malicious guest can trigger the out-of-bounds memory access flaw, leading to a QEMU process crash.

Mitigation and Prevention

Learn about the immediate steps to take, long-term security practices, and patching procedures.

Immediate Steps to Take

QEMU users should apply patches immediately to prevent exploitation of this vulnerability.

Long-Term Security Practices

Regularly update QEMU and monitor security advisories for any new vulnerabilities.

Patching and Updates

Ensure timely installation of security patches and updates to keep QEMU secure.