CVE-2026-64105 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: vgic: Free private_irqs when init fails after allocation
Companion to commit 250f25367b58 ("KVM: arm64: Tear down vGIC on failed vCPU creation"), which added the missing kvm_vgic_vcpu_destroy() call to the kvm_share_hyp() failure path in kvm_arch_vcpu_create(). The kvm_vgic_vcpu_init() failure path immediately above it has the same shape and still needs the same cleanup.
Call kvm_vgic_vcpu_destroy() when kvm_vgic_vcpu_init() fails so private IRQs allocated before a redistributor iodev registration failure are released before the failed vCPU is freed.
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Analysis
by VulDB Data Team • 07/20/2026
This vulnerability resides within the Linux kernel's KVM subsystem, specifically affecting ARM64 virtualization implementations through the virtual generic interrupt controller component. The issue manifests as a resource management flaw in the vGIC initialization process where private IRQs are not properly released when vCPU creation fails after allocation. The vulnerability represents a classic case of improper error handling and resource cleanup that can lead to system instability and potential denial of service conditions. When the kernel attempts to initialize virtual CPU instances within KVM environments, it allocates private IRQ resources as part of the vGIC setup process. However, if subsequent initialization steps fail during redistributor iodev registration, the previously allocated IRQ resources remain unreleased, creating a memory leak scenario that can accumulate over time and eventually exhaust available interrupt resources.
The technical flaw stems from an inconsistent error handling pattern within the KVM architecture's ARM64 implementation where the cleanup logic exists for one failure path but is missing from another equivalent path. The vulnerability specifically affects the kvm_vgic_vcpu_init() function which handles vGIC initialization for virtual CPUs, and it occurs when the function encounters a failure after allocating private IRQ resources but before completing the full initialization sequence. This creates a resource leak condition where interrupt vectors remain allocated in kernel memory despite the failed vCPU creation attempt. The issue is particularly concerning because it operates at the hypervisor level where proper resource management directly impacts system stability and performance, especially in environments with high vCPU creation rates or frequent virtual machine provisioning activities.
The operational impact of this vulnerability extends beyond simple resource leaks to potentially compromise system availability and performance. When multiple vCPU creation attempts fail in succession, the accumulation of unreleased private IRQs can lead to interrupt exhaustion conditions that prevent new VMs from being properly initialized or cause existing VMs to experience degraded interrupt handling performance. This vulnerability affects virtualization environments running on ARM64 architectures where KVM is utilized for guest virtual machine management, including cloud infrastructure platforms, containerized environments, and embedded systems using virtualization technologies. The resource leak could manifest as gradual performance degradation, increased memory consumption, or complete system unresponsiveness under sustained load conditions with repeated vCPU creation failures.
Mitigation strategies should focus on ensuring proper error handling throughout the KVM initialization sequence by implementing consistent cleanup procedures across all failure paths in the vGIC implementation. System administrators should monitor for signs of interrupt resource exhaustion and consider applying kernel patches that address this specific resource management issue. The fix involves adding a call to kvm_vgic_vcpu_destroy() within the kvm_vgic_vcpu_init() failure path, ensuring that private IRQ resources allocated prior to the redistributor iodev registration failure are properly released before the failed vCPU instance is freed from memory. This approach aligns with established security practices for resource management and follows the principle of least privilege by ensuring all allocated resources are properly accounted for during error conditions. The vulnerability's classification as a resource leak issue relates to CWE-404, which addresses improper resource release or cleanup, and may also map to ATT&CK technique T1499.004 related to network disruption through resource exhaustion attacks. Organizations should prioritize applying security patches to their kernel versions and implement monitoring for abnormal interrupt usage patterns that might indicate resource leak conditions.