CVE-2026-98863 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel security, particularly those managing KVM-based systems, should be aware of this vulnerability and take steps to verify and apply patches. Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability to prevent potential re-entry into L2 with stale, unpinned PFNs. This includes reviewing and updating Linux kernel versions to ensure they are not vulnerable and and

Why it matters

Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability to prevent potential re-entry into L2 with stale, unpinned PFNs.

• Potential re-entry into L2 with stale, unpinned PFNs
• Need to verify and apply patches for Linux kernel versions affected by this vulnerability
• Importance of monitoring Linux kernel updates and patches for potential vulnerabilities

Technical summary

The Linux kernel vulnerability CVE-2026-98863 allows re-pending of GET_NESTED_STATE_PAGES if getting said pages fails in the KVM_RUN path, potentially leading to re-entry into L2 with stale, unpinned PFNs. This vulnerability affects Linux kernel versions and has been resolved in the Linux kernel. Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability to prevent potential re-entry into L2 with stale, unpinned PFNs. The vulnerability has been resolved in the Linux kernel, and defenders should review and update Linux kernel versions to ensure they are not vulnerable.

Defensive priority

Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability.

Recommended defensive actions

• Verify and apply patches for Linux kernel versions affected by this vulnerability
• Review and update Linux kernel versions to ensure they are not vulnerable
• Monitor Linux kernel updates and patches for potential vulnerabilities
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description and affected versions. The vulnerability has been resolved in the Linux kernel, and defenders should verify and apply patches for Linux kernel versions affected by this vulnerability. The source item provides additional information on the vulnerability, and defenders should review and update Linux kernel versions to ensure they are not vulnerable.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.