CVE-2026-98928 Linux CVE debrief

Who should care

Defenders responsible for KVM deployments on arm64 should assess exposure to this vulnerability and ensure proper handling of sve_state. This involves verifying the Linux kernel version and applying patches to prevent potential issues.

Why it matters

The Linux kernel vulnerability in KVM on arm64 requires defenders to assess exposure, verify kernel versions, and apply patches to prevent potential issues with GUEST_HAS_SVE flag and sve_state handling.

• Defenders must verify Linux kernel versions to ensure patches are applied
• KVM deployments on arm64 require assessment for exposure to this vulnerability
• Proper handling of sve_state is crucial to prevent potential issues

Technical summary

The Linux kernel vulnerability involves deriving the GUEST_HAS_SVE flag from the SVE feature bit at EL2 in KVM on arm64. A host setting the flag without the bit could result in a vCPU with a NULL sve_state, causing the world switch to load the guest's SVE state from an incorrect source. The issue has been resolved through patches to the Linux kernel. Defenders should prioritize verifying the Linux kernel version and applying patches to prevent potential issues with KVM on arm64. This involves assessing the exposure of KVM deployments to this vulnerability and ensuring that the sve_state is properly handled. The CVE record and source item provide details about the vulnerability and its resolution in the Linux.

Defensive priority

Defenders should prioritize verifying the Linux kernel version and applying patches to prevent potential issues with KVM on arm64. This involves assessing the exposure of KVM deployments to this vulnerability and ensuring that the sve_state is properly handled.

Recommended defensive actions

• Verify Linux kernel version and apply patches to prevent potential issues with KVM on arm64
• Assess exposure of KVM deployments to this vulnerability
• Ensure proper handling of sve_state in KVM
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details about the vulnerability and its resolution in the Linux kernel. The affected versions and patches are specified, allowing defenders to assess exposure and apply necessary fixes.

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.