CVE-2026-64555

Received Received - Intake

KVM: arm64 Nested Virtualization SPSR_EL2 State Corruption

Publication date: 2026-07-27

Last updated on: 2026-07-30

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: nv: Fix SPSR_EL2 restore in kvm_hyp_handle_mops() kvm_hyp_handle_mops() resets the single-step state machine as part of rewinding state for a MOPS exception by modifying vcpu_cpsr() and writing the result directly into hardware. In the case of nested virtualization, vcpu_cpsr() is a synthetic value such that the rest of KVM can deal with vEL2 cleanly. That means the value requires translation before being written into hardware, which is unfortunately missing from the MOPS handler. Fix it by directly modifying SPSR_EL2 and avoiding the synthetic state altogether, which will be resynchronized on the next 'full' exit back to KVM.

CVSS Scores

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Meta Information

Published

2026-07-27

Last Modified

2026-07-30

Generated

2026-08-17

AI Q&A

2026-07-28

EPSS Evaluated

2026-08-15

NVD

CVE-2026-64555

EUVD

EUVD-2026-49606

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel affects KVM for arm64 nested virtualization. It involves a missing translation step when restoring the SPSR_EL2 register during MOPS exceptions. The issue occurs because kvm_hyp_handle_mops() modifies a synthetic vcpu_cpsr() value without converting it properly for hardware use, potentially causing incorrect state restoration in nested virtualization scenarios.

Detection Guidance

This vulnerability is specific to the Linux kernel's KVM implementation for arm64 and requires kernel-level detection. There are no direct network or system commands to detect it as it is a code-level issue. Monitoring kernel logs for KVM-related errors or crashes may indicate exploitation attempts.

Impact Analysis

This vulnerability could lead to incorrect execution of nested virtual machines, causing crashes, data corruption, or privilege escalation in affected systems. Users running virtualized environments on arm64 hardware with KVM may experience instability or security issues if the flaw is exploited.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it is a low-level kernel issue in KVM for arm64 nested virtualization. It involves a missing translation step in SPSR_EL2 restore during MOPS exceptions, which could lead to incorrect state handling but does not inherently impact data protection or privacy controls required by these regulations.

Mitigation Strategies

Apply the latest kernel patches from your Linux distribution that address this specific KVM vulnerability. If nested virtualization is used, consider disabling it temporarily until the patch is applied. Monitor vendor advisories for updates.

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