CVE-2026-93076 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel security, particularly those managing device_dax and fsdev_dax configurations, should assess exposure and verify kernel versions. They should also review and apply patches for affected Linux kernel versions and monitor for potential stale vmemmap_shift values in shared pgmaps. This includes verifying Linux kernel versions, reviewing compensating controls for exposed systems, and checking relevant monitoring, detection

Why it matters

Defenders should verify Linux kernel versions and assess exposure based on device_dax to fsdev_dax rebinding scenarios to ensure proper vmemmap configuration.

• Verification of Linux kernel versions is necessary to determine exposure
• Rebinding of static devices from device_dax to fsdev_dax may require updates to pgmap configurations
• Stale vmemmap_shift values could potentially affect vmemmap construction for order-0 folios

Technical summary

The Linux kernel vulnerability involves a stale vmemmap_shift value persisting on shared pgmaps when rebinding static devices from device_dax to fsdev_dax. The fix explicitly zeros vmemmap_shift before devm_memremap_pages() to ensure the vmemmap is built for order-0 folios as required by fsdev_dax. This change ensures that the vmemmap configuration is properly set for fsdev_dax, preventing potential issues with vmemmap construction for order-0 folios. Defenders should verify Linux kernel versions and assess exposure based on device_dax to fsdev_dax rebinding scenarios.

Defensive priority

Defenders should verify Linux kernel versions and assess exposure based on device_dax to fsdev_dax rebinding scenarios.

Recommended defensive actions

• Verify Linux kernel versions and assess device_dax to fsdev_dax rebinding scenarios
• Review and apply patches for affected Linux kernel versions
• Monitor for potential stale vmemmap_shift values in shared pgmaps
• 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
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the Linux kernel vulnerability and its resolution. References include official CVE Program and NVD records, as well as kernel.org links. To verify exposure, defenders should check Linux kernel versions and assess device_dax to fsdev_dax rebinding scenarios. The source details are limited, so explicit evidence-limit language and defensive verification tasks are necessary.

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.