CVE-2026-46147 KVM: arm64: Fix pin leak and publication ordering in __pkvm_init_vcpu()
A race condition and memory leak in Linux KVM arm64 vCPU initialization can cause resource exhaustion or inconsistent state, requiring kernel patching.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-46147?
CVE-2026-46147 is a medium-severity vulnerability in Linux kernel, published on 28 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-401
Which versions are affected by CVE-2026-46147?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46147?
Apply the vendor's patch.
Is CVE-2026-46147 being exploited?
There is no known exploitation of CVE-2026-46147 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88908, BELL-CVE-2026-46147, DEBIAN-CVE-2026-46147, GHSA-m978-f9gm-gj2j, ROOT-OS-DEBIAN-11-CVE-2026-46147, ROOT-OS-DEBIAN-12-CVE-2026-46147 and 4 more.