CVE-2026-98109 Linux CVE debrief

Who should care

Linux kernel maintainers, users, and administrators should assess exposure and verify patched versions to prevent potential DEBUG_LOCKS warnings. This involves reviewing Linux kernel versions, focusing on Bluetooth HCI core changes and mutex initialization, and monitoring for warnings. Maintainers and users must prioritize patching to avoid race condition exploitation and resulting system instability. Security teams should track exposure and verify patch

Why it matters

A race condition vulnerability in the Linux kernel's Bluetooth HCI core during device registration can trigger a DEBUG_LOCKS warning. Defenders should verify patched versions and assess exposure.

• Verification of patched Linux kernel versions is required to prevent DEBUG_LOCKS warnings
• Linux kernel maintainers and users should assess exposure to this vulnerability

Technical summary

The Linux kernel's Bluetooth HCI core has a race condition vulnerability during device registration. When the power_on work item runs concurrently with device initialization, it can trigger a DEBUG_LOCKS warning by attempting to lock an uninitialized mutex. The issue is resolved by rearranging the initialization and queue_work() call in hci_register_dev(). This change ensures that device structures and extensions are fully initialized before asynchronous tasks can access them, preventing the mutex locking issue. The fix involves moving the queue_work() call to after idr_init(&hdev->adv_monitors_idr) and msft_register(hdev) to synchronize device initialization and work item execution.

Defensive priority

Linux kernel maintainers and users should assess exposure and verify patched versions.

Recommended defensive actions

• Review Linux kernel versions and assess exposure
• Verify patched versions are applied
• Monitor for potential DEBUG_LOCKS warnings
• 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 NVD entry provide details on the vulnerability in the Linux kernel's Bluetooth HCI core during device registration. This vulnerability can trigger a DEBUG_LOCKS warning due to a race condition. The issue arises when the power_on work item runs concurrently with device initialization, leading to an attempt to lock an uninitialized mutex. To verify patched versions and assess exposure, defenders should review Linux kernel versions, focusing on Bluetooth HCI core changes and mutex initialization. The CVE details and N.

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.