Several security issues were fixed in QEMU.
It was discovered that QEMU incorrectly handled bochs-display devices. A local attacker in a guest could use this to cause a denial of service or possibly execute arbitrary code in the host. This issue only affected Ubuntu 19.10. (CVE-2019-15034)
21 May 2020
A security issue affects these releases of Ubuntu and its derivatives:
Several security issues were fixed in QEMU.
It was discovered that QEMU incorrectly handled bochs-display devices. A local attacker in a guest could use this to cause a denial of service or possibly execute arbitrary code in the host. This issue only affected Ubuntu 19.10. (CVE-2019-15034)
It was discovered that QEMU incorrectly handled memory during certain VNC operations. A remote attacker could possibly use this issue to cause QEMU to consume resources, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. (CVE-2019-20382)
It was discovered that QEMU incorrectly generated QEMU Pointer Authentication signatures on ARM. A local attacker could possibly use this issue to bypass PAuth. This issue only affected Ubuntu 19.10. (CVE-2020-10702)
Ziming Zhang discovered that QEMU incorrectly handled ATI VGA emulation. A local attacker in a guest could use this issue to cause QEMU to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2020-11869)
Aviv Sasson discovered that QEMU incorrectly handled Slirp networking. A remote attacker 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 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 19.10. (CVE-2020-1983)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart all QEMU virtual machines to make all the necessary changes.