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.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | KVM: SEV: Do cache maintenance on the source VM *before* clearing SEV state | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:46:53.611Z
Reserved: 2026-09-25T10:25:14.366Z
Link: CVE-2026-98718
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:25.363
Modified: 2026-10-18T16:17:25.363
Link: CVE-2026-98718
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.