A QEMU security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, and 20.10.

==========================================================================
Ubuntu Security Notice USN-4650-1
November 30, 2020

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

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

- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Several security issues were fixed in QEMU.

Software Description:
- qemu: Machine emulator and virtualizer

Details:

Alexander Bulekov discovered that QEMU incorrectly handled SDHCI device
emulation. 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 on the host. In the default installation, when QEMU is used with
libvirt, attackers would be isolated by the libvirt AppArmor profile.
(CVE-2020-17380)

Sergej Schumilo, Cornelius Aschermann, and Simon Wrner discovered that QEMU
incorrectly handled USB device emulation. An attacker inside the guest
could use this issue to cause QEMU to crash, resulting in a denial of
service. (CVE-2020-25084)

Sergej Schumilo, Cornelius Aschermann, and Simon Wrner discovered that QEMU
incorrectly handled SDHCI device emulation. An attacker inside the guest
could use this issue to cause QEMU to crash, resulting in a denial of
service. (CVE-2020-25085)

Gaoning Pan, Yongkang Jia, and Yi Ren discovered that QEMU incorrectly
handled USB device emulation. An attacker inside the guest could use this
issue to cause QEMU to crash, resulting in a denial of service.
(CVE-2020-25624)

It was discovered that QEMU incorrectly handled USB device emulation. An
attacker inside the guest could use this issue to cause QEMU to hang,
resulting in a denial of service. (CVE-2020-25625)

Cheolwoo Myung discovered that QEMU incorrectly handled USB device
emulation. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. (CVE-2020-25723)

Gaoning Pan discovered that QEMU incorrectly handled ATI graphics device
emulation. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. This issue only affected Ubuntu
20.04 LTS and Ubuntu 20.10. (CVE-2020-27616)

Gaoning Pan discovered that QEMU incorrectly handled networking. An
attacker inside the guest could use this issue to cause QEMU to crash,
resulting in a denial of service. (CVE-2020-27617)

Update instructions:

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

Ubuntu 20.10:
qemu-system 1:5.0-5ubuntu9.2
qemu-system-arm 1:5.0-5ubuntu9.2
qemu-system-mips 1:5.0-5ubuntu9.2
qemu-system-misc 1:5.0-5ubuntu9.2
qemu-system-ppc 1:5.0-5ubuntu9.2
qemu-system-s390x 1:5.0-5ubuntu9.2
qemu-system-sparc 1:5.0-5ubuntu9.2
qemu-system-x86 1:5.0-5ubuntu9.2
qemu-system-x86-microvm 1:5.0-5ubuntu9.2
qemu-system-x86-xen 1:5.0-5ubuntu9.2

Ubuntu 20.04 LTS:
qemu-system 1:4.2-3ubuntu6.10
qemu-system-arm 1:4.2-3ubuntu6.10
qemu-system-mips 1:4.2-3ubuntu6.10
qemu-system-misc 1:4.2-3ubuntu6.10
qemu-system-ppc 1:4.2-3ubuntu6.10
qemu-system-s390x 1:4.2-3ubuntu6.10
qemu-system-sparc 1:4.2-3ubuntu6.10
qemu-system-x86 1:4.2-3ubuntu6.10
qemu-system-x86-microvm 1:4.2-3ubuntu6.10
qemu-system-x86-xen 1:4.2-3ubuntu6.10

Ubuntu 18.04 LTS:
qemu-system 1:2.11+dfsg-1ubuntu7.34
qemu-system-arm 1:2.11+dfsg-1ubuntu7.34
qemu-system-mips 1:2.11+dfsg-1ubuntu7.34
qemu-system-misc 1:2.11+dfsg-1ubuntu7.34
qemu-system-ppc 1:2.11+dfsg-1ubuntu7.34
qemu-system-s390x 1:2.11+dfsg-1ubuntu7.34
qemu-system-sparc 1:2.11+dfsg-1ubuntu7.34
qemu-system-x86 1:2.11+dfsg-1ubuntu7.34

Ubuntu 16.04 LTS:
qemu-system 1:2.5+dfsg-5ubuntu10.48
qemu-system-aarch64 1:2.5+dfsg-5ubuntu10.48
qemu-system-arm 1:2.5+dfsg-5ubuntu10.48
qemu-system-mips 1:2.5+dfsg-5ubuntu10.48
qemu-system-misc 1:2.5+dfsg-5ubuntu10.48
qemu-system-ppc 1:2.5+dfsg-5ubuntu10.48
qemu-system-s390x 1:2.5+dfsg-5ubuntu10.48
qemu-system-sparc 1:2.5+dfsg-5ubuntu10.48
qemu-system-x86 1:2.5+dfsg-5ubuntu10.48

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

References:
  https://usn.ubuntu.com/4650-1
CVE-2020-17380, CVE-2020-25084, CVE-2020-25085, CVE-2020-25624,
CVE-2020-25625, CVE-2020-25723, CVE-2020-27616, CVE-2020-27617

Package Information:
  https://launchpad.net/ubuntu/+source/qemu/1:5.0-5ubuntu9.2
  https://launchpad.net/ubuntu/+source/qemu/1:4.2-3ubuntu6.10
  https://launchpad.net/ubuntu/+source/qemu/1:2.11+dfsg-1ubuntu7.34
  https://launchpad.net/ubuntu/+source/qemu/1:2.5+dfsg-5ubuntu10.48