CVE-2026-74356 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel-based systems, particularly those using the vhost component, should assess exposure and prioritize patching. System administrators and security teams should verify kernel versions and apply patches to prevent potential livelock issues.

Why it matters

The Linux kernel vulnerability in the vhost component can cause a livelock in the host, and defenders should prioritize verifying kernel versions and applying patches to prevent potential issues.

• Potential livelock in the host due to incorrect return value from `vhost_get_avail_idx`
• Need to verify Linux kernel version and apply patches to fix the vulnerability
• Potential impact on system performance and stability

Technical summary

The `vhost_get_avail_idx` function in the Linux kernel incorrectly returns whether all entries have been consumed, instead of reporting whether it has updated `vq->avail_idx`. This can cause the host to livelock if the guest is not making progress. The issue was introduced by commit d3bb267bbdcb and was fixed by multiple subsequent commits. Defenders should prioritize verifying the Linux kernel version and applying patches to fix the vulnerability. They should also monitor for potential livelock issues in the vhost component and review system configurations to ensure that vhost is properly configured.

Defensive priority

Defenders should prioritize verifying the Linux kernel version and applying patches to fix the vulnerability. They should also monitor for potential livelock issues in the vhost component.

Recommended defensive actions

• Verify Linux kernel version and apply patches to fix the vulnerability
• Monitor for potential livelock issues in the vhost component
• Review system configurations and ensure that vhost is properly configured
• 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
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The vulnerability is caused by an incorrect return value from `vhost_get_avail_idx`, which can lead to a livelock in the host. The issue was introduced by commit d3bb267bbdcb and was fixed by multiple subsequent commits.

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.