Host panic via user-triggered VM ioctl warning
Published Oct 18, 2026 · Updated Oct 18, 2026
A warning in arm64 KVM in Linux 7.0 allows local users to crash a protected-mode host through an unknown VM ioctl. The kvm_pkvm_ioctl_allowed() function raises a warning when a userspace-supplied ioctl number has no entry in vm_ioctl_caps[], rather than simply rejecting it. Access to a VM file descriptor and a pKVM host are required; panic_on_warn turns the warning into a host panic, while otherwise the warning taints the kernel.
Summary
What happened
A warning in arm64 KVM in Linux 7.0 allows local users to crash a protected-mode host through an unknown VM ioctl. The kvm_pkvm_ioctl_allowed() function raises a warning when a userspace-supplied ioctl number has no entry in vm_ioctl_caps[], rather than simply rejecting it. Access to a VM file descriptor and a pKVM host are required; panic_on_warn turns the warning into a host panic, while otherwise the warning taints the kernel.
The record
- CVE
- CVE-2026-98470
- Published
- Oct 18, 2026
- Updated
- Oct 18, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Oct 18, 2026CVE publishedPublication date reported by the CVE source.
- Oct 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.0
- Affected versionversion=b12b3b04f6ba072ca5a618a75e546c996be94bd1 <49d9d295d69d07e850cae35933ba8519e2915f26
- Affected versionversion=b12b3b04f6ba072ca5a618a75e546c996be94bd1 <cc53eb5c6515e3221314624a22c9da9c80a67f63
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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