A QEMU security update has been released for Ubuntu 18.04 LTS, 20.04 LTS, and 21.10.

==========================================================================
Ubuntu Security Notice USN-5307-1
February 28, 2022

qemu vulnerabilities
==========================================================================

A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 21.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in QEMU.

Software Description:
- qemu: Machine emulator and virtualizer

Details:

Gaoning Pan discovered that QEMU incorrectly handled the floppy disk
emulator. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. (CVE-2021-20196)

Gaoning Pan discovered that the QEMU vmxnet3 NIC emulator incorrectly
handled certain values. An attacker inside the guest could use this issue
to cause QEMU to crash, resulting in a denial of service. (CVE-2021-20203)

It was discovered that the QEMU vhost-user GPU device contained several
security issues. An attacker inside the guest could use these issues to
cause QEMU to crash, resulting in a denial of service, leak sensitive
information, or possibly execute arbitrary code. This issue only affected
Ubuntu 21.10. (CVE-2021-3544, CVE-2021-3545, CVE-2021-3546)

It was discovered that QEMU incorrectly handled bulk transfers from SPICE
clients. A remote attacker could use this issue to cause QEMU to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2021-3682)

It was discovered that the QEMU UAS device emulation incorrectly handled
certain stream numbers. An attacker inside the guest could use this issue
to cause QEMU to crash, resulting in a denial of service, or possibly
execute arbitrary code. This issue only affected Ubuntu 21.10.
(CVE-2021-3713)

It was discovered that the QEMU virtio-net device incorrectly handled
certain buffer addresses. An attacker inside the guest could use this issue
to cause QEMU to crash, resulting in a denial of service, or possibly
execute arbitrary code. (CVE-2021-3748)

It was discovered that the QEMU SCSI device emulation incorrectly handled
certain MODE SELECT commands. An attacker inside the guest could possibly
use this issue to cause QEMU to crash, resulting in a denial of service.
(CVE-2021-3930)

It was discovered that the QEMU ACPI logic incorrectly handled certain
values. An attacker inside the guest could possibly use this issue to cause
QEMU to crash, resulting in a denial of service. This issue only affected
Ubuntu 21.10. (CVE-2021-4158)

Jietao Xiao, Jinku Li, Wenbo Shen, and Nanzi Yang discovered that the QEMU
virtiofsd device incorrectly handled permissions when creating files. An
attacker inside the guest could use this issue to create files inside the
directory shared by virtiofs with unintended permissions, possibly allowing
privilege escalation. This issue only affected Ubuntu 21.10.
(CVE-2022-0358)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 21.10:
qemu-system 1:6.0+dfsg-2expubuntu1.2
qemu-system-arm 1:6.0+dfsg-2expubuntu1.2
qemu-system-mips 1:6.0+dfsg-2expubuntu1.2
qemu-system-misc 1:6.0+dfsg-2expubuntu1.2
qemu-system-ppc 1:6.0+dfsg-2expubuntu1.2
qemu-system-s390x 1:6.0+dfsg-2expubuntu1.2
qemu-system-sparc 1:6.0+dfsg-2expubuntu1.2
qemu-system-x86 1:6.0+dfsg-2expubuntu1.2
qemu-system-x86-microvm 1:6.0+dfsg-2expubuntu1.2
qemu-system-x86-xen 1:6.0+dfsg-2expubuntu1.2

Ubuntu 20.04 LTS:
qemu-system 1:4.2-3ubuntu6.21
qemu-system-arm 1:4.2-3ubuntu6.21
qemu-system-mips 1:4.2-3ubuntu6.21
qemu-system-misc 1:4.2-3ubuntu6.21
qemu-system-ppc 1:4.2-3ubuntu6.21
qemu-system-s390x 1:4.2-3ubuntu6.21
qemu-system-sparc 1:4.2-3ubuntu6.21
qemu-system-x86 1:4.2-3ubuntu6.21
qemu-system-x86-microvm 1:4.2-3ubuntu6.21
qemu-system-x86-xen 1:4.2-3ubuntu6.21

Ubuntu 18.04 LTS:
qemu-system 1:2.11+dfsg-1ubuntu7.39
qemu-system-arm 1:2.11+dfsg-1ubuntu7.39
qemu-system-mips 1:2.11+dfsg-1ubuntu7.39
qemu-system-misc 1:2.11+dfsg-1ubuntu7.39
qemu-system-ppc 1:2.11+dfsg-1ubuntu7.39
qemu-system-s390x 1:2.11+dfsg-1ubuntu7.39
qemu-system-sparc 1:2.11+dfsg-1ubuntu7.39
qemu-system-x86 1:2.11+dfsg-1ubuntu7.39

After a standard system update you need to restart all QEMU virtual
machines to make all the necessary changes.

References:
  https://ubuntu.com/security/notices/USN-5307-1
CVE-2021-20196, CVE-2021-20203, CVE-2021-3544, CVE-2021-3545,
CVE-2021-3546, CVE-2021-3682, CVE-2021-3713, CVE-2021-3748,
CVE-2021-3930, CVE-2021-4158, CVE-2022-0358

Package Information:
  https://launchpad.net/ubuntu/+source/qemu/1:6.0+dfsg-2expubuntu1.2
  https://launchpad.net/ubuntu/+source/qemu/1:4.2-3ubuntu6.21
  https://launchpad.net/ubuntu/+source/qemu/1:2.11+dfsg-1ubuntu7.39