CVE-2026-98718
Low risk· EPSS 5%Exploitation Probability (EPSS)
Low risk5th percentile - higher than 5% of all known CVEs
Summary
In the Linux kernel's KVM SEV, cache maintenance is performed after clearing the SEV state on the source VM during intra-host migration. This creates a window where memory reclaim can free a page without a prior cache flush, and a subsequent hardware flush overwrites the new page owner's data with the guest's old ciphertext.
Risk Assessment
This can cause data corruption or leakage between virtual machines, violating guest isolation and confidentiality in SEV environments.
Recommendation
Update the Linux kernel to a version containing the fix that performs cache maintenance before clearing the SEV state on the source VM.
Other vulnerabilities in Linux kernel (KVM SEV)
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state Explicitly flush caches after intra-host migration before clearing "SEV active" on the source VM, as doing cache maintenance afterwards creates a tiny window where memory reclaim could return memory to the host without performing a cache flush, e.g. as pointed out by Sashiko: CPU1 in sev_migrate_from(): src->active = false; CPU2 running concurrent unmap: Since active is false, the automatic cache flush in sev_guest_memory_reclaimed is skipped. The host frees and reallocates the page. CPU1 in sev_migrate_from(): sev_writeback_caches(src_kvm); Executes a hardware cache flush (wbnoinvd), which writes the guest's old dirty ciphertext over the new page owner's data.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS