CVE-2022-1789 in Bluetooth
Summary
by MITRE • 06/02/2022
With shadow paging enabled, the INVPCID instruction results in a call to kvm_mmu_invpcid_gva. If INVPCID is executed with CR0.PG=0, the invlpg callback is not set and the result is a NULL pointer dereference.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 08/17/2025
The vulnerability identified as CVE-2022-1789 represents a critical null pointer dereference flaw within the kernel-based virtual machine subsystem of the Linux operating system. This issue specifically manifests when shadow paging is enabled in virtualized environments, creating a scenario where the INVPCID instruction fails to properly initialize memory management components. The vulnerability stems from the improper handling of the INVPCID instruction when the paging bit in CR0 register is disabled, which fundamentally alters the execution path and memory management behavior within the kernel's virtualization layer.
The technical root cause of this vulnerability lies in the kvm_mmu_invpcid_gva function's failure to properly validate the virtualization context when processing INVPCID instructions. When CR0.PG=0, the paging mechanism is disabled, yet the system continues to attempt to invoke memory management callbacks that are only valid when paging is enabled. This creates a scenario where the invlpg callback pointer remains uninitialized, leading to an immediate null pointer dereference upon execution. The flaw occurs at the intersection of virtualization management and memory management subsystems, where the assumption that certain memory management callbacks are always available proves incorrect in specific virtualization configurations.
The operational impact of this vulnerability is severe as it can lead to system crashes and potential denial of service conditions within virtualized environments. Attackers capable of executing privileged code within a guest operating system can leverage this vulnerability to cause kernel panics or system instability, effectively disrupting virtual machine operations and potentially compromising the entire virtualization infrastructure. The vulnerability is particularly dangerous in cloud computing environments where multiple virtual machines share the same physical host, as a single compromised guest could potentially affect the stability of other virtual machines running on the same hypervisor. This type of vulnerability aligns with CWE-476 which identifies null pointer dereference as a critical weakness in software systems.
Mitigation strategies for CVE-2022-1789 should focus on both immediate patching and operational hardening measures. The primary solution involves applying the official kernel patches that address the null pointer dereference in the kvm_mmu_invpcid_gva function by ensuring proper validation of the paging state before attempting to invoke memory management callbacks. System administrators should also consider implementing runtime monitoring to detect anomalous INVPCID instruction usage patterns and configure virtualization environments to disable shadow paging when not strictly required. Additionally, organizations should maintain strict access controls within virtualized environments to limit the potential attack surface, as this vulnerability requires execution privileges within a guest operating system to be effectively exploited. The remediation approach should align with ATT&CK technique T1059.003 which focuses on command and scripting interpreter usage, ensuring that virtualization management components are properly hardened against potentially malicious instruction sequences.