Linux Kernel up to 6.18.29/7.0.6/7.1-rc1 KVM __pkvm_init_vcpu vcpus[] locking

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.18.29/7.0.6/7.1-rc1. It has been rated as critical. The impacted element is the function __pkvm_init_vcpu of the component KVM. Performing a manipulation of the argument vcpus[] results in locking. This vulnerability is identified as CVE-2026-46147. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.29/7.0.6/7.1-rc1. This affects the function __pkvm_init_vcpu of the component KVM. The manipulation of the argument vcpus[] with an unknown input leads to a locking vulnerability. CWE is classifying the issue as CWE-667. The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors. This is going to have an impact on availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-46147 since 05/13/2026. Technical details are known, but no exploit is available.

Upgrading to version 6.18.30, 7.0.7 or 7.1-rc2 eliminates this vulnerability. Applying the patch 7d3c27b54253cda91dc4d2c1bfc109c490837ab9/6d69c0ed978f7f0efd053fc98390f25ab77c1aea/73b9c1e5da84cd69b1a86e374e450817cd051371 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-1700). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• F5 F5OS
• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel
• Siemens SIMATIC S7
• F5 BIG-IP
• Dell Secure Connect Gateway
• IBM Security Verify Access

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.1-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion