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USN-5071-1 Not scored

linux, linux-aws, linux-aws-5.4, linux-azure, linux-azure-5.4, linux-gcp, linux-gcp-5.4, linux-gke, linux-gke-5.4, linux-gkeop, linux-gkeop-5.4, linux-kvm, linux-oracle, linux-oracle-5.4 vulnerabilities

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) 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) It was discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not ensure enough processing time was given to perform cleanups of large SEV VMs. A local attacker could use this to cause a denial of service (soft lockup). (CVE-2020-36311) It was discovered that the KVM hypervisor implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. An attacker who could start and control a VM could possibly use this to expose sensitive information or execute arbitrary code. (CVE-2021-22543) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612)

Exploit probability Not scored
Published September 8, 2021
Required by Not available
Last source change June 3, 2026

02 / AFFECTED SOFTWARE

Affected packages

Ubuntu:18.04:LTS linux-aws-5.4

23 explicit affected versions

Ubuntu:18.04:LTS linux-azure-5.4

22 explicit affected versions

Ubuntu:18.04:LTS linux-gcp-5.4

22 explicit affected versions

Ubuntu:18.04:LTS linux-gke-5.4

17 explicit affected versions

Ubuntu:18.04:LTS linux-gkeop-5.4

17 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.4

23 explicit affected versions

Ubuntu:20.04:LTS linux

40 explicit affected versions

Ubuntu:20.04:LTS linux-aws

35 explicit affected versions

Ubuntu:20.04:LTS linux-azure

32 explicit affected versions

Ubuntu:20.04:LTS linux-gcp

32 explicit affected versions

Ubuntu:20.04:LTS linux-gke

12 explicit affected versions

Ubuntu:20.04:LTS linux-gkeop

12 explicit affected versions

Ubuntu:20.04:LTS linux-kvm

30 explicit affected versions

Ubuntu:20.04:LTS linux-oracle

33 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities USN-5071-1

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) 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) It was discovered that the KVM hypervisor implementation for AMD processors in the Linux kernel did not ensure enough processing time was given to perform cleanups of large SEV VMs. A local attacker could use this to cause a denial of service (soft lockup). (CVE-2020-36311) It was discovered that the KVM hypervisor implementation in the Linux kernel did not properly perform reference counting in some situations, leading to a use-after-free vulnerability. An attacker who could start and control a VM could possibly use this to expose sensitive information or execute arbitrary code. (CVE-2021-22543) Murray McAllister discovered that the joystick device interface in the Linux kernel did not properly validate data passed via an ioctl(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code on systems with a joystick device registered. (CVE-2021-3612)

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05 / REFERENCES

Further evidence