NULL Pointer Dereference Affecting qemu package, versions <1:6.2+dfsg-2ubuntu5


Severity

Recommended
low

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.48% (39th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-UBUNTU2510-QEMU-15025317
  • published17 Jan 2026
  • disclosed26 May 2021

Introduced: 26 May 2021

CVE-2021-20196  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Ubuntu:25.10 qemu to version 1:6.2+dfsg-2ubuntu5 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream qemu package and not the qemu package as distributed by Ubuntu. See How to fix? for Ubuntu:25.10 relevant fixed versions and status.

A NULL pointer dereference flaw was found in the floppy disk emulator of QEMU. This issue occurs while processing read/write ioport commands if the selected floppy drive is not initialized with a block device. This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

CVSS Base Scores

version 3.1