CVE-2021-20196
This flaw allows a privileged guest user to crash the QEMU process on the host, resulting in a denial of service.
Does this matter?
Lower severity and a low EPSS score (0.48%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 6.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
- EPSS
- 0.48% probability · 41th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- qemu/qemu · debian/debian linux
- Source
- secalert@redhat.com
EPSS 0.5% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugs.launchpad.net/qemu/+bug/1912780Exploit, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210708-0004/Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/01/28/1Mailing List, Patch, Third Party Advisory
- https://bugs.launchpad.net/qemu/+bug/1912780Exploit, Patch, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/04/msg00002.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/09/msg00008.htmlMailing List, Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210708-0004/Third Party Advisory
- https://www.openwall.com/lists/oss-security/2021/01/28/1Mailing List, Patch, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.