NULL pointer dereference in Qemu

CVE-2021-20196

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.

EPSS: 0.005 (38.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.

Affected products

  • Qemu — versions 5.2.0
  • Debian Debian_linux — versions 9.0, 10.0
  • N/a Qemu — versions vulnerable up to (including) qemu 5.2.0

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-20196?
CVE-2021-20196 is a medium-severity vulnerability in Qemu, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2021-05-26.
How severe is CVE-2021-20196?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-20196 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.