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.

• CWE-476
• CWE-476

• 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

Published

May 26, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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