CVE-2026-64284 KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits

What is CVE-2026-64284?

CVE-2026-64284 is a high-severity vulnerability in Linux kernel, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits

Move the handling of fastpath userspace exits into vendor code to ensure KVM runs vendor specific operations that need to run before userspace gains control of the vCPU. E.g. for VMX (and soon to be for SVM as well), KVM needs to flush the PML buffer prior to exiting to userspace, otherwise any memory written by the final KVM_RUN might never be flagged as dirty.

Note, waiting to snapshot CR0 and CR3 until svm_handle_exit() is flawed in general, as that risks consuming stale state in a fastpath handler. That will be addressed in a future change.

Weakness: CWE-367, CWE-362

Which versions are affected by CVE-2026-64284?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64284?

Apply the vendor's patch.

Is CVE-2026-64284 being exploited?

There is no known exploitation of CVE-2026-64284 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64284, DEBIAN-CVE-2026-64284, GHSA-gv38-jcpj-j76h, ROOT-OS-UBUNTU-2204-CVE-2026-64284, UBUNTU-CVE-2026-64284.