CVE-2021-47062 KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs

What is CVE-2021-47062?

CVE-2021-47062 is a medium-severity vulnerability in Linux kernel, published on 29 Feb 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

KVM: SVM: Use online_vcpus, not created_vcpus, to iterate over vCPUs

Use the kvm_for_each_vcpu() helper to iterate over vCPUs when encrypting VMSAs for SEV, which effectively switches to use online_vcpus instead of created_vcpus. This fixes a possible null-pointer dereference as created_vcpus does not guarantee a vCPU exists, since it is updated at the very beginning of KVM_CREATE_VCPU. created_vcpus exists to allow the bulk of vCPU creation to run in parallel, while still correctly restricting the max number of max vCPUs.

Weakness: CWE-476

Which versions are affected by CVE-2021-47062?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47062?

No fix has been published for CVE-2021-47062 yet. Limit exposure of the affected software until one is available.

Is CVE-2021-47062 being exploited?

There is no known exploitation of CVE-2021-47062 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-2948-3mj2-4gw2, UBUNTU-CVE-2021-47062.