CVE Catalog

CVE-2026-64284

HighCVSS 7.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.12%

2th percentile - higher than 2% of all known CVEs

Summary

In the Linux kernel KVM for x86, a vulnerability was found where fastpath userspace exits are handled before vendor-specific code runs. This can lead to missing operations such as flushing the PML buffer before returning control to userspace.

Risk Assessment

An attacker can exploit this to avoid marking memory as dirty, potentially leading to data integrity issues or privilege escalation.

Recommendation

Apply the patch that moves fastpath exit handling into vendor code to ensure necessary operations run before returning to userspace.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS