CVE-2026-98456 Linux CVE debrief

Who should care

Linux kernel maintainers, users, and administrators should assess exposure and prioritize verification of affected systems. Affected operators, platforms, vulnerability-management, and security teams should review Linux kernel versions and configurations for potential exposure, verify system logs for signs of exploitation, and apply patches or updates when available.

Why it matters

A race condition vulnerability in the Linux kernel's Bluetooth management subsystem can lead to an out-of-bounds write, requiring verification of affected systems and potential patching or updates.

• Verify Linux kernel versions and configurations for potential exposure
• Check system logs for signs of exploitation
• Prioritize patching or updating affected systems

Technical summary

The read_unconf_index_list() function in the Linux kernel's Bluetooth management subsystem is vulnerable to a race condition, which can lead to an out-of-bounds write. The function counts unconfigured controllers before allocating its response and then checks device flags again while filling it. During asynchronous controller setup, the worker can set HCI_UNCONFIGURED and clear HCI_SETUP between the two passes. A controller omitted from the allocation count can then become eligible for the fill pass, causing an out-of-bounds write to rp->index[].

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

Recommended defensive actions

• Review Linux kernel versions and configurations for potential exposure
• Verify system logs for signs of exploitation
• Apply patches or updates when available
• 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
• 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

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but its scope and impact require further verification. Linux kernel maintainers and users should verify affected systems, review Linux kernel versions and configurations for potential exposure, and check system logs for signs of exploitation. Evidence is limited to public sources and may not reflect all affected systems or potential impacts.

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.