==========================================================================
Ubuntu Security Notice USN-4725-1
February 08, 2021

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:

It was discovered that QEMU incorrectly handled memory in iSCSI emulation.
An attacker inside the guest could possibly use this issue to obtain
sensitive information. This issue only affected Ubuntu 16.04 LTS, Ubuntu
18.04 LTS, and Ubuntu 20.04 LTS. (CVE-2020-11947)

Alexander Bulekov discovered that QEMU incorrectly handled Intel e1000e
emulation. An attacker inside the guest could use this issue to cause QEMU
to crash, resulting in a denial of service. (CVE-2020-15859)

Alexander Bulekov discovered that QEMU incorrectly handled memory region
cache. 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-2020-27821)

Cheol-woo Myung discovered that QEMU incorrectly handled Intel e1000e
emulation. An attacker inside the guest could use this issue to cause a
denial of service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04
LTS, and Ubuntu 20.10. (CVE-2020-28916)

Wenxiang Qian discovered that QEMU incorrectly handled ATAPI emulation. An
attacker inside the guest could use this issue to cause QEMU to crash,
resulting in a denial of service. (CVE-2020-29443)

It was discovered that QEMU incorrectly handled VirtFS directory sharing.
An attacker inside the guest could use this issue to cause QEMU to crash,
resulting in a denial of service. (CVE-2021-20181)

Update instructions:

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

Ubuntu 20.10:
  qemu-system                     1:5.0-5ubuntu9.4
  qemu-system-arm                 1:5.0-5ubuntu9.4
  qemu-system-mips                1:5.0-5ubuntu9.4
  qemu-system-misc                1:5.0-5ubuntu9.4
  qemu-system-ppc                 1:5.0-5ubuntu9.4
  qemu-system-s390x               1:5.0-5ubuntu9.4
  qemu-system-sparc               1:5.0-5ubuntu9.4
  qemu-system-x86                 1:5.0-5ubuntu9.4
  qemu-system-x86-microvm         1:5.0-5ubuntu9.4
  qemu-system-x86-xen             1:5.0-5ubuntu9.4

Ubuntu 20.04 LTS:
  qemu-system                     1:4.2-3ubuntu6.12
  qemu-system-arm                 1:4.2-3ubuntu6.12
  qemu-system-mips                1:4.2-3ubuntu6.12
  qemu-system-misc                1:4.2-3ubuntu6.12
  qemu-system-ppc                 1:4.2-3ubuntu6.12
  qemu-system-s390x               1:4.2-3ubuntu6.12
  qemu-system-sparc               1:4.2-3ubuntu6.12
  qemu-system-x86                 1:4.2-3ubuntu6.12
  qemu-system-x86-microvm         1:4.2-3ubuntu6.12
  qemu-system-x86-xen             1:4.2-3ubuntu6.12

Ubuntu 18.04 LTS:
  qemu-system                     1:2.11+dfsg-1ubuntu7.35
  qemu-system-arm                 1:2.11+dfsg-1ubuntu7.35
  qemu-system-mips                1:2.11+dfsg-1ubuntu7.35
  qemu-system-misc                1:2.11+dfsg-1ubuntu7.35
  qemu-system-ppc                 1:2.11+dfsg-1ubuntu7.35
  qemu-system-s390x               1:2.11+dfsg-1ubuntu7.35
  qemu-system-sparc               1:2.11+dfsg-1ubuntu7.35
  qemu-system-x86                 1:2.11+dfsg-1ubuntu7.35

Ubuntu 16.04 LTS:
  qemu-system                     1:2.5+dfsg-5ubuntu10.49
  qemu-system-aarch64             1:2.5+dfsg-5ubuntu10.49
  qemu-system-arm                 1:2.5+dfsg-5ubuntu10.49
  qemu-system-mips                1:2.5+dfsg-5ubuntu10.49
  qemu-system-misc                1:2.5+dfsg-5ubuntu10.49
  qemu-system-ppc                 1:2.5+dfsg-5ubuntu10.49
  qemu-system-s390x               1:2.5+dfsg-5ubuntu10.49
  qemu-system-sparc               1:2.5+dfsg-5ubuntu10.49
  qemu-system-x86                 1:2.5+dfsg-5ubuntu10.49

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

References:
  https://usn.ubuntu.com/4725-1
  CVE-2020-11947, CVE-2020-15859, CVE-2020-27821, CVE-2020-28916,
  CVE-2020-29443, CVE-2021-20181

Package Information:
  https://launchpad.net/ubuntu/+source/qemu/1:5.0-5ubuntu9.4
  https://launchpad.net/ubuntu/+source/qemu/1:4.2-3ubuntu6.12
  https://launchpad.net/ubuntu/+source/qemu/1:2.11+dfsg-1ubuntu7.35
  https://launchpad.net/ubuntu/+source/qemu/1:2.5+dfsg-5ubuntu10.49