A use-after-free vulnerability in the Linux kernel's KVM subsystem for ARM64 processors has been disclosed as CVE-2026-89775. The flaw affects hosts with nested virtualization enabled, where a guest virtual machine can read and write to previously freed host kernel memory. The discovering researcher indicates this may facilitate guest-to-host code execution, though kernel maintainers have not independently verified exploitation claims at time of reporting.

Which products are affected?

Linux kernel (ARM64 KVM subsystem)

What should defenders do?

Apply the latest Linux kernel patches that address the KVM ARM64 memory handling code. Disable nested virtualization if not required. Monitor vendor advisories and kernel security mailing lists for follow-up updates. Ensure systems are running kernel versions containing the fix for CVE-2026-89775.

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Linux Kernel KVM ARM64 Vulnerability Exposes Host Memory to Guests

CVE-2026-89775: Use-after-free flaw in nested virtualization allows guest read-write access to host memory

CyberIntel DeskPublished 2 days agoUpdated less than a minute ago1 min read

Linux Kernel KVM ARM64 Vulnerability Exposes Host Memory to Guests

Key Takeaways

CVE-2026-89775 is a use-after-free flaw in the Linux kernel KVM ARM64 subsystem.
The vulnerability is triggered when nested virtualization is enabled on the host.
A guest VM may read and write to freed host kernel memory.
The researcher claims this could allow guest-to-host code execution, but this remains unconfirmed by maintainers.

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