CVE-2026-99009 Linux CVE debrief

Who should care

Linux kernel developers and administrators responsible for maintaining Linux-based systems should assess exposure and apply updates if necessary. They should also review compensating controls for exposed systems and monitor system logs for potential exploitation attempts. Affected operators, platforms, and security teams need to be aware of the vulnerability and its potential impact.

Why it matters

The Linux kernel's Bluetooth RFCOMM implementation is vulnerable to a circular dependency lock issue, potentially leading to a denial of service. Linux kernel developers and administrators should assess exposure and apply updates if necessary.

• Denial of service due to circular dependency lock issue
• Potential disruption to Bluetooth connectivity

Technical summary

The Linux kernel's Bluetooth RFCOMM implementation is vulnerable to a circular dependency lock issue. This issue can be triggered when an RFCOMM connect() is issued while a BR/EDR link is being authenticated, potentially leading to a denial of service. The vulnerability affects Linux kernel developers and administrators responsible for maintaining Linux-based systems. The issue has been addressed by Linux kernel developers. Affected systems should be updated to prevent potential exploitation. The vulnerability is related to the Bluetooth RFCOMM implementation in the Linux kernel.

Defensive priority

Apply kernel updates to address the Bluetooth RFCOMM vulnerability

Recommended defensive actions

• Verify kernel version and apply updates if necessary
• Monitor system logs for potential exploitation attempts
• 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
• 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

Evidence notes

The CVE record and associated source item provide details on the vulnerability, including a description of the issue and affected kernel versions. The Linux kernel's Bluetooth RFCOMM implementation is vulnerable to a circular dependency lock issue. Evidence is based on CVE Program records and associated source items. Defenders should verify kernel versions and assess exposure. The vulnerability has been addressed by Linux kernel developers.

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.