CVE-2026-80873
Received Received - Intake

KVM: arm64 Nested SError Exception ESR_EL2 Write Vulnerability

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: nv: Write ESR_EL2 for injected nested SError exceptions kvm_inject_el2_exception() writes ESR_EL2 for synchronous exceptions but not for SError. enter_exception64() does not write ESR_ELx for any exception type, so the constructed syndrome is dropped. A guest L2 hypervisor taking a nested SError observes stale ESR_EL2. This affects both kvm_inject_nested_serror() and the EASE path in kvm_inject_nested_sea(). Write ESR_EL2 for except_type_serror, matching except_type_sync.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-05
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-80873
EUVD
EUVD-2026-71503

Affected Vendors & Products

Currently, no data is known.

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is in the Linux kernel's KVM (Kernel-based Virtual Machine) for ARM64 systems. It involves nested virtualization where a guest hypervisor running inside a virtual machine (L2) may receive incorrect error information. Specifically, when a nested SError (System Error) exception occurs, the kernel fails to write the ESR_EL2 register, which holds error details. This leaves the guest hypervisor with stale or incorrect error data.

Detection Guidance

This vulnerability is specific to the Linux kernel's KVM implementation for arm64 systems. Detection requires checking the kernel version and KVM module behavior. Use commands like 'uname -a' to verify kernel version and 'lsmod | grep kvm' to check KVM module status. Monitor kernel logs for nested SError exceptions.

Impact Analysis

If you use virtualization with ARM64 systems, this flaw could cause guest hypervisors to malfunction or crash due to incorrect error handling. It may lead to unexpected behavior in virtual machines, data corruption, or denial of service if the guest relies on accurate error reporting for recovery.

Mitigation Strategies

Apply the latest kernel patches from your Linux distribution to resolve this issue. If patches are unavailable, consider disabling nested virtualization in KVM by setting 'nested=0' in the KVM module parameters. Restart the KVM service after making changes.

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