Vulnerability in x86/hyperv Package: NULL Dereference in set_hv_tscchange_cb()

Kernel Updated 02 Oct 2025

Summary

29/11/2021

Disclosed on

N/A

Severity

No i

Fix available

Unrated

Severity

Not published

CVSS Score

GSD-2021-1002246: x86/hyperv: Fix NULL deref in set_hv_tscchange_cb() if Hyper-V setup fails. Affects Kernel versions >= 93286261de1b46339aa27cd4c639b21778f6cade, < b20ec58f8a6f4fef32cc71480ddf824584e24743. No fix is published. How to fix ↓

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Background

The x86/hyperv package is a component of the Linux Kernel that provides support for running Linux as a guest operating system on Microsoft Hyper-V hypervisor. It includes various functionalities and drivers specific to Hyper-V, enabling seamless integration and optimized performance. However, a vulnerability has been identified in the package that can lead to a NULL dereference in the set_hv_tscchange_cb() function if the Hyper-V setup fails.

Vulnerability Detail

The vulnerability arises when the Hyper-V setup fails, causing a NULL pointer dereference in the set_hv_tscchange_cb() function. This can potentially be exploited by an attacker to trigger a denial-of-service condition or execute arbitrary code with kernel privileges. The impact and attack plausibility of this vulnerability have not been proven yet. The vulnerability was introduced in version v4.16 of the Linux Kernel and has been fixed in version v4.19.218 through commit b20ec58f8a6f4fef32cc71480ddf824584e24743.

How To Fix

No fixed version is published for this vulnerability.

To fix this vulnerability, it is recommended to update the Linux Kernel to version v4.19.218 or later. This can be done by pulling the latest updates from the official Linux Kernel repository using the following command:

$ git pull https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

After updating the Kernel, rebuild and reinstall it on the affected systems.

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Workaround

There is no specific workaround mentioned for this vulnerability.

Conclusion

The x86/hyperv package in the Linux Kernel is vulnerable to a NULL dereference in the set_hv_tscchange_cb() function. To mitigate this vulnerability, it is crucial to update the Linux Kernel to version v4.19.218 or later. For further assistance or support in vulnerability remediation, please contact DevNack.com.

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