CVE-2026-74573 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel systems, particularly those using iommu/arm-smmu-v3-iommufd, should assess exposure and prioritize patching. This includes operators, platform administrators, vulnerability management teams, and security teams who manage Linux kernel deployments. They should review system configurations, monitor system logs, and verify affected scope to ensure proper mitigation of the vulnerability.

Why it matters

CVE-2026-74573 is a Linux kernel vulnerability that requires exactly one Stream ID for a vDEVICE in iommu/arm-smmu-v3-iommufd. Defenders should prioritize verifying and applying patches for affected Linux kernel versions.

• Verify and apply patches for Linux kernel versions affected by this vulnerability
• Review system configurations for iommu/arm-smmu-v3-iommufd usage
• Monitor system logs for potential exploitation attempts

Technical summary

The Linux kernel vulnerability CVE-2026-74573 requires exactly one Stream ID for a vDEVICE in iommu/arm-smmu-v3-iommufd. The vulnerability has been resolved by adding an arm_vsmmu_vdevice_init() op to reject vDEVICEs with -EOPNOTSUPP when master->num_streams is not one. This change ensures that devices with multiple streams are properly handled, preventing potential security risks associated with the vulnerability. Affected Linux kernel versions should be assessed for exposure, and patches should be applied as necessary.

Defensive priority

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

Recommended defensive actions

• Verify Linux kernel versions and apply patches if necessary
• Review system configurations for iommu/arm-smmu-v3-iommufd usage
• Monitor system logs for potential exploitation attempts
• 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 resolution and affected versions. The Linux kernel vulnerability CVE-2026-74573 requires exactly one Stream ID for a vDEVICE in iommu/arm-smmu-v3-iommufd. The vulnerability has been resolved by adding an arm_vsmmu_vdevice_init() op to reject vDEVICEs with -EOPNOTSUPP when master->num_streams is not one. Evidence is limited to CVE Program and NVD records, which may not cover all affected versions or deployment contexts. Defenders should verify and apply

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.