CVE-2021-4207: Debian Linux

High severity, CVSS 8.2. EPSS: 0.4% chance of exploitation in the next 30 days.

A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values `cursor->header.width` and `cursor->header.height` can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only
• Qemu Qemu: before 7.0.0 (fixed in 7.0.0)
• Red Hat Enterprise Linux: version 8.0 only

Published 2022-04-29. Last modified 2026-06-17.