VulnerabilityPublished 19 Oct 2026Updated 28 Oct 2026

CVE-2026-98718: Linux kernel · KVM: SEV: Do cache maintenance on the source VM before clearing SEV state

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-98718· High

Not known to be exploited.

Data as of 28 Oct 2026, 12:46 UTC

Severity

High

Rated by Threat Radar · CVSS not yet scored by NVD

Exploitation evidence

Disclosed: evidence found.
CVE published 18 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-42.42 24 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1016.17 16 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1016.18 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-ibm`pkg:deb/ubuntu/linux-ibm?arch=source&distro=resolute`Other threats	Affected 6.19.0-1002.2 – 7.0.0-1017.17 14 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-oracle`pkg:deb/ubuntu/linux-oracle?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1015.16 16 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-riscv`pkg:deb/ubuntu/linux-riscv?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5.1 – 7.0.0-42.42.1 13 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel to perform cache maintenance explicitly before clearing the SEV active state on the source VM during migration. Users should update to patched kernel versions that include this fix. No additional mitigation steps are indicated.

Description

A vulnerability in the Linux kernel's KVM SEV implementation involves improper cache maintenance timing during intra-host VM migration. The issue arises because cache flushes are performed after clearing the SEV active state on the source VM, creating a small window where memory reclaim operations may incorrectly skip cache flushes. This can lead to stale or incorrect memory data being exposed to the host or other VMs.

Impact

The vulnerability creates a small timing window during VM migration where memory pages could be reclaimed by the host without proper cache flushing. This could result in the host or other VMs seeing stale or incorrect memory contents, potentially undermining the confidentiality guarantees of SEV. However, the severity is rated low, indicating limited impact or exploitability.

Summary

The Linux kernel's KVM SEV feature had a flaw where cache maintenance was done after clearing the SEV active state on the source VM during migration. This ordering allowed a race condition: once the SEV active flag was cleared, concurrent memory reclaim operations could skip cache flushes, causing the host to free and reallocate pages without proper cache synchronization. The fix ensures explicit cache flushes occur before clearing the SEV state, preventing potential memory exposure due to stale cache data.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 12:46 UTC

Technical details

References

Community reviews

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