NULL pointer dereference in QEMU - CVE-2021-20196

Vulnerability identifier: #VU63775

CSH Severity: Low

CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-20196

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the floppy disk emulator of QEMU. A privileged guest can trigger a NULL pointer dereference error and cause a denial of service. 

QEMU
SUSE Linux Enterprise Micro
SUSE MicroOS
SUSE Linux Enterprise Server
SUSE Linux Enterprise Realtime Extension
SUSE Linux Enterprise Module for Server Applications
SUSE Linux Enterprise Module for Basesystem
Ubuntu
openEuler
qemu-ipxe
qemu-seabios
qemu-vgabios
qemu-system-s390x (Ubuntu package)
qemu-system (Ubuntu package)
qemu-system-x86 (Ubuntu package)
qemu-system-sparc (Ubuntu package)
qemu-system-mips (Ubuntu package)
qemu-system-arm (Ubuntu package)
qemu-system-misc (Ubuntu package)
qemu-system-ppc (Ubuntu package)
qemu-tools-debuginfo
qemu-block-ssh-debuginfo
qemu-debugsource
qemu-block-ssh
qemu-guest-agent
qemu-guest-agent-debuginfo
qemu-lang
qemu-tools
qemu-block-iscsi-debuginfo
qemu-block-iscsi
qemu-block-curl-debuginfo
qemu-block-curl
qemu-audio-sdl-debuginfo
qemu-audio-sdl
qemu-audio-pa-debuginfo
qemu-audio-pa
qemu-audio-oss-debuginfo
qemu-audio-oss
qemu-audio-alsa-debuginfo
qemu-audio-alsa
qemu
qemu-ui-curses-debuginfo
qemu-s390-debuginfo
qemu-s390
qemu-x86
qemu-ppc-debuginfo
qemu-ppc
qemu-arm-debuginfo
qemu-arm
qemu-ui-curses
qemu-kvm
qemu-block-rbd-debuginfo
qemu-block-rbd
qemu-ui-sdl-debuginfo
qemu-ui-sdl
qemu-ui-gtk-debuginfo
qemu-ui-gtk
qemu-help
qemu-img
qemu-debuginfo
qemu-microvm
qemu-x86-debuginfo
qemu-ui-spice-app-debuginfo
qemu-ui-spice-app
qemu-system-x86-microvm (Ubuntu package)
qemu-system-x86-xen (Ubuntu package)
qemu-chardev-baum-debuginfo
qemu-chardev-baum
qemu-s390x-debuginfo
qemu-s390x
qemu-skiboot
qemu-hw-s390x-virtio-gpu-ccw
qemu-hw-s390x-virtio-gpu-ccw-debuginfo
qemu-ksm
qemu-hw-display-virtio-gpu-pci-debuginfo
qemu-hw-display-virtio-gpu-pci
qemu-hw-display-virtio-gpu-debuginfo
qemu-hw-display-virtio-gpu
qemu-ui-spice-core-debuginfo
qemu-ui-spice-core
qemu-ui-opengl-debuginfo
qemu-ui-opengl
qemu-audio-spice-debuginfo
qemu-audio-spice
qemu-chardev-spice
qemu-chardev-spice-debuginfo
qemu-hw-display-qxl
qemu-hw-display-qxl-debuginfo
qemu-hw-display-virtio-vga
qemu-hw-display-virtio-vga-debuginfo
qemu-hw-usb-redirect
qemu-hw-usb-redirect-debuginfo
qemu-sgabios

Install update from vendor's website.

QEMU - update to 6.0.0
qemu-ipxe - addressed in versions 1.0.0+-11.34.2, 1.0.0+-63.4, 1.0.0+-150300.109.2
qemu-seabios - addressed in versions 1.12.0_0_ga698c89-63.4, 1.12.1+-11.34.2, 1.14.0_0_g155821a-150300.109.2
qemu-vgabios - addressed in versions 1.12.0_0_ga698c89-63.4, 1.12.1+-11.34.2, 1.14.0_0_g155821a-150300.109.2
qemu-system-s390x (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-x86 (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-sparc (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-mips (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-arm (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-misc (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-ppc (Ubuntu package) - addressed in versions 1:2.11+dfsg-1ubuntu7.39, 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-tools-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-ssh-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-debugsource - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-ssh - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-guest-agent - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-guest-agent-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-lang - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-tools - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-iscsi-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-iscsi - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-curl-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-curl - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-audio-sdl-debuginfo - update to 3.1.1.1-63.4
qemu-audio-sdl - update to 3.1.1.1-63.4
qemu-audio-pa-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-audio-pa - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-audio-oss-debuginfo - update to 3.1.1.1-63.4
qemu-audio-oss - update to 3.1.1.1-63.4
qemu-audio-alsa-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-audio-alsa - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-curses-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-s390-debuginfo - update to 3.1.1.1-63.4
qemu-s390 - update to 3.1.1.1-63.4
qemu-x86 - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ppc-debuginfo - addressed in versions 3.1.1.1-63.4, 5.2.0-150300.109.2
qemu-ppc - addressed in versions 3.1.1.1-63.4, 5.2.0-150300.109.2
qemu-arm-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-arm - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-curses - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-kvm - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-rbd-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-block-rbd - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-sdl-debuginfo - update to 3.1.1.1-63.4
qemu-ui-sdl - update to 3.1.1.1-63.4
qemu-ui-gtk-debuginfo - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-gtk - addressed in versions 3.1.1.1-63.4, 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-seabios - update to 4.1.0-63
qemu-help - update to 4.1.0-63
qemu-img - update to 4.1.0-63
qemu-guest-agent - update to 4.1.0-63
qemu-debugsource - update to 4.1.0-63
qemu-debuginfo - update to 4.1.0-63
qemu - update to 4.1.0-63
qemu-block-curl - update to 4.1.0-63
qemu-block-iscsi - update to 4.1.0-63
qemu-block-rbd - update to 4.1.0-63
qemu-block-ssh - update to 4.1.0-63
qemu-microvm - update to 4.2.1-11.34.2
qemu-x86-debuginfo - addressed in versions 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-spice-app-debuginfo - addressed in versions 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-ui-spice-app - addressed in versions 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-debuginfo - addressed in versions 4.2.1-11.34.2, 5.2.0-150300.109.2
qemu-system-x86-microvm (Ubuntu package) - addressed in versions 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-system-x86-xen (Ubuntu package) - addressed in versions 1:4.2-3ubuntu6.21, 1:6.0+dfsg-2expubuntu1.2
qemu-chardev-baum-debuginfo - update to 5.2.0-150300.109.2
qemu-chardev-baum - update to 5.2.0-150300.109.2
qemu-s390x-debuginfo - update to 5.2.0-150300.109.2
qemu-s390x - update to 5.2.0-150300.109.2
qemu-skiboot - update to 5.2.0-150300.109.2
qemu-hw-s390x-virtio-gpu-ccw - update to 5.2.0-150300.109.2
qemu-hw-s390x-virtio-gpu-ccw-debuginfo - update to 5.2.0-150300.109.2
qemu-ksm - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-gpu-pci-debuginfo - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-gpu-pci - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-gpu-debuginfo - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-gpu - update to 5.2.0-150300.109.2
qemu-ui-spice-core-debuginfo - update to 5.2.0-150300.109.2
qemu-ui-spice-core - update to 5.2.0-150300.109.2
qemu-ui-opengl-debuginfo - update to 5.2.0-150300.109.2
qemu-ui-opengl - update to 5.2.0-150300.109.2
qemu-audio-spice-debuginfo - update to 5.2.0-150300.109.2
qemu-audio-spice - update to 5.2.0-150300.109.2
qemu-chardev-spice - update to 5.2.0-150300.109.2
qemu-chardev-spice-debuginfo - update to 5.2.0-150300.109.2
qemu-hw-display-qxl - update to 5.2.0-150300.109.2
qemu-hw-display-qxl-debuginfo - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-vga - update to 5.2.0-150300.109.2
qemu-hw-display-virtio-vga-debuginfo - update to 5.2.0-150300.109.2
qemu-hw-usb-redirect - update to 5.2.0-150300.109.2
qemu-hw-usb-redirect-debuginfo - update to 5.2.0-150300.109.2
qemu-sgabios - addressed in versions 8-11.34.2, 8-63.4, 8-150300.109.2

• 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://bugzilla.redhat.com/show_bug.cgi?id=1919210

• Ubuntu update for qemu
• SUSE update for qemu
• SUSE update for qemu
• SUSE update for qemu
• SUSE update for qemu
• openEuler update for qemu