LSN-0081-1

Description

Kernel Live Patch Security Notice Maxim Levitsky discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not properly prevent a guest VM from enabling AVIC in nested guest VMs. An attacker in a guest VM could use this to write to portions of the host's physical memory.(CVE-2021-3653) Maxim Levitsky and Paolo Bonzini discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel allowed a guest VM to disable restrictions on VMLOAD/VMSAVE in a nested guest. An attacker in a guest VM could use this to read or write portions of the host's physical memory.(CVE-2021-3656) Andy Nguyen discovered that the netfilter subsystem in the Linux kernel contained an out-of-bounds write in its setsockopt() implementation. A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.(CVE-2021-22555) It was discovered that the virtual file system implementation in the Linux kernel contained an unsigned to signed integer conversion error. A local attacker could use this to cause a denial of service (system crash) or execute arbitrary code.(CVE-2021-33909)

Affected Systems

• ubuntu•linux

  all | < 4.4.0-214.246 | < 4.15.0-156.163 | < 5.4.0-84.94

• ubuntu•linux-gcp

  all | < 5.4.0-1052.56

• ubuntu•linux-gke

  all | < 5.4.0-1052.55

• ubuntu•linux-gke-4.15

  all

• ubuntu•linux-gke-5.4

  all | < 5.4.0-1052.55~18.04.1

• ubuntu•linux-gkeop

  all | < 5.4.0-1023.24

• ubuntu•linux-gkeop-5.4

  all | < 5.4.0-1023.24~18.04.1

• ubuntu•linux-hwe

  all | < 4.15.0-156.163~16.04.1

• ubuntu•linux-hwe-5.4

  all | < 5.4.0-84.94~18.04.1

• ubuntu•linux-lts-xenial

  all | < 4.4.0-214.246~14.04.1

• ubuntu•linux-oem

  all

References (5)

• https://ubuntu.com/security/notices/LSN-0081-1
• https://ubuntu.com/security/CVE-2021-3653
• https://ubuntu.com/security/CVE-2021-3656
• https://ubuntu.com/security/CVE-2021-22555
• https://ubuntu.com/security/CVE-2021-33909