CVE-2026-46147
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
A vulnerability in the Linux kernel related to vCPU initialization in KVM for arm64 has been fixed. Issues regarding pin leaks and vCPU publication ordering have been addressed by implementing appropriate safeguards in the code.
Risk Assessment
Organizations may be exposed to memory leaks and synchronization issues, potentially leading to unpredictable behavior of virtual machines and security vulnerabilities.
Recommendation
It is recommended to update the Linux kernel to the latest version to eliminate this vulnerability and ensure proper memory management in virtual environments.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix pin leak and publication ordering in __pkvm_init_vcpu() Two bugs exist in the vCPU initialisation path: 1. If a check fails after hyp_pin_shared_mem() succeeds, the cleanup path jumps to 'unlock' without calling unpin_host_vcpu() or unpin_host_sve_state(), permanently leaking pin references on the host vCPU and SVE state pages. Extract a register_hyp_vcpu() helper that performs the checks and the store. When register_hyp_vcpu() returns an error, call unpin_host_vcpu() and unpin_host_sve_state() inline before falling through to the existing 'unlock' label. 2. register_hyp_vcpu() publishes the new vCPU pointer into 'hyp_vm->vcpus[]' with a bare store, allowing a concurrent caller of pkvm_load_hyp_vcpu() to observe a partially initialised vCPU object. Ensure the store uses smp_store_release() and the load uses smp_load_acquire(). While 'vm_table_lock' currently serialises the store and the load, these barriers ensure the reader sees the fully initialised 'hyp_vcpu' object even if there were a lockless path or if the lock's own ordering guarantees were insufficient for nested object initialization.