Linux Kernel up to 6.1.19/6.2.6 KVM null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.19/6.2.6. It has been rated as critical. Affected by this issue is some unknown functionality of the component KVM. Performing a manipulation results in null pointer dereference. This vulnerability is cataloged as CVE-2022-49933. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.1.19/6.2.6. This affects an unknown function of the component KVM. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Reset eVMCS controls in VP assist page during hardware disabling Reset the eVMCS controls in the per-CPU VP assist page during hardware disabling instead of waiting until kvm-intel's module exit. The controls are activated if and only if KVM creates a VM, i.e. don't need to be reset if hardware is never enabled. Doing the reset during hardware disabling will naturally fix a potential NULL pointer deref bug once KVM disables CPU hotplug while enabling and disabling hardware (which is necessary to fix a variety of bugs). If the kernel is running as the root partition, the VP assist page is unmapped during CPU hot unplug, and so KVM's clearing of the eVMCS controls needs to occur with CPU hot(un)plug disabled, otherwise KVM could attempt to write to a CPU's VP assist page after it's unmapped.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2022-49933 since 05/01/2025. The exploitability is told to be difficult. Neither technical details nor an exploit are publicly available.

Upgrading to version 6.1.20 or 6.2.7 eliminates this vulnerability. Applying the patch afb26bfc01db6ef4728e96314f08431934ffe833/01aa8e5704bac9fcd7401eb1a74a375fba594203/2916b70fc342719f570640de07251b7f91feebdb is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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