CVE-2021-4032 Null dereference in kernel

What is CVE-2021-4032?

CVE-2021-4032 is a medium-severity vulnerability in Linux kernel, published on 21 Jan 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A vulnerability was found in the Linux kernel's KVM subsystem in arch/x86/kvm/lapic.c kvm_free_lapic when a failure allocation was detected. In this flaw the KVM subsystem may crash the kernel due to mishandling of memory errors that happens during VCPU construction, which allows an attacker with special user privilege to cause a denial of service. This flaw affects kernel versions prior to 5.15 rc7.

Weakness: CWE-459

Which versions are affected by CVE-2021-4032?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-4032?

No fix has been published for CVE-2021-4032 yet. Limit exposure of the affected software until one is available.

Is CVE-2021-4032 being exploited?

There is no known exploitation of CVE-2021-4032 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-89wc-v8x9-wrv5, UBUNTU-CVE-2021-4032.