CVE-2026-93821 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution maintainers, and users with hotplug or rescan operations in their systems should assess exposure and prioritize verification of affected systems, especially those with hotplug or rescan operations. They should review Linux kernel configurations and versions to determine exposure and apply patches or updates to fixed versions if available.

Why it matters

CVE-2026-93821 is a vulnerability in the Linux kernel's PCI: altera component that requires verification of exposure and potential system impacts, especially in systems with hotplug or rescan operations.

• Verify potential for system crashes due to use-after-free issues.
• Assess exposure of Linux kernel configurations and versions.
• Prioritize patching or updating to fixed versions if available.

Technical summary

The Linux kernel's PCI: altera component had a vulnerability that could lead to use-after-free issues or system crashes due to a lack of rescan lock during root bus removal. This has been addressed by holding the pci_rescan_remove_lock lock while stopping and removing a root bus to avoid racing with concurrent rescan or hotplug operations triggered via sysfs. The vulnerability requires verification of exposure and potential system impacts, especially in systems with hotplug or rescan operations. Users should review Linux kernel configurations and versions to determine exposure and apply patches or updates to fixed versions if available.

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems, especially those with hotplug or rescan operations.

Recommended defensive actions

• Review Linux kernel configurations and versions to determine exposure.
• Verify system crash and use-after-free vulnerability conditions.
• Apply patch or update to fixed version if available.
• 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.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability. Three source references from the Linux kernel Git repository are available. The vulnerability has been resolved in the Linux kernel, and users should verify their configurations and versions to determine exposure. The Linux kernel maintainers, Linux distribution maintainers, and users with hotplug or rescan operations in their systems should assess exposure and prioritize verification. The fix is related to the PCI: altera component and involves protecting root bus.

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.