CVE-2021-20196

Description

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 Metrics

• v3.1•MEDIUM•Score: 6.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
• v2.0•LOW•Score: 2.1AV:L/AC:L/Au:N/C:N/I:N/A:P

EPSS Trends

Current EPSS score: 0.04%• Percentile: 12%

Techniques & Countermeasures

• CWE-476•NULL Pointer Dereference

  The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

• debian•debian_linux

  9.0 | 10.0

• qemu•qemu

  5.2.0

References (5)

• https://bugs.launchpad.net/qemu/+bug/1912780
• https://www.openwall.com/lists/oss-security/2021/01/28/1
• https://security.netapp.com/advisory/ntap-20210708-0004/
• https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html
• https://lists.debian.org/debian-lts-announce/2022/09/msg00008.html