Vulnerability in Kernel: KVM x86/mm: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit
Summary
GSD-2021-1000396: KVM: x86/mmu: Alloc page for PDPTEs when shadowing 32-bit NPT with 64-bit. Affects Kernel versions >= ee6268ba3a6861b2806e569bff7fe91fbdf846dd, < c8b49e01a23b0f5a97dc977812adaf042b474eb7. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
The Kernel is a critical component of the Linux operating system that provides core functionalities and acts as an interface between the hardware and software layers. It manages system resources, facilitates communication between processes, and ensures security and stability. The KVM (Kernel-based Virtual Machine) subsystem within the Kernel enables virtualization on x86-based systems. It allows multiple virtual machines to run concurrently on a single physical machine. The x86/mm subsystem handles memory management for x86-based systems, including the translation of virtual addresses to physical addresses. This vulnerability affects the Kernel's x86/mm subsystem when shadowing a 32-bit Nested Page Table (NPT) with a 64-bit one.
Vulnerability Detail
The vulnerability arises when allocating Page Directory Pointer Table Entries (PDPTEs) during the shadowing process. In the context of virtualization, shadowing involves creating a shadow page table to optimize memory access for virtual machines. When shadowing a 32-bit NPT with a 64-bit one, the Kernel fails to allocate a page for PDPTEs, leading to a potential memory corruption issue. An attacker with access to a virtual machine could exploit this vulnerability to gain elevated privileges or execute arbitrary code within the host system. The impact and attack plausibility of this vulnerability have not been proven yet.
How To Fix
No fixed version is published for this vulnerability.
The vulnerability has been fixed in Linux Kernel version v5.10.37 by commit c8b49e01a23b0f5a97dc977812adaf042b474eb7. To fix this vulnerability, users are advised to update their Kernel to the latest stable version available. This can be done by downloading the updated Kernel source code from the official Git repository (https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/) and following the installation instructions provided by the Kernel documentation.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
No specific workaround has been mentioned for this vulnerability.
Conclusion
The vulnerability in the Kernel's x86/mm subsystem when shadowing a 32-bit NPT with a 64-bit one has been identified and fixed in Linux Kernel version v5.10.37. Users are advised to update their Kernel to the latest stable version to mitigate the risk. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for Kernel →
FAQ
The Kernel is a critical component of the Linux operating system that provides core functionalities and acts as an interface between the hardware and software layers.
KVM (Kernel-based Virtual Machine) is a subsystem within the Kernel that enables virtualization on x86-based systems, allowing multiple virtual machines to run concurrently on a single physical machine.
x86/mm is a subsystem within the Kernel that handles memory management for x86-based systems, including the translation of virtual addresses to physical addresses.
Shadowing in virtualization refers to the process of creating a shadow page table to optimize memory access for virtual machines.
If exploited, this vulnerability could allow an attacker with access to a virtual machine to gain elevated privileges or execute arbitrary code within the host system.
Related vulnerabilities
Recent vulnerabilities recorded for Kernel.
Follow Vulert in Google
Get more Vulert vulnerability and dependency-security updates in Google Search and AI results.