CVE-2026-98739 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, as well as users of Linux-based systems that utilize Bluetooth RFCOMM functionality, should be aware of this vulnerability and take steps to mitigate its impact. Linux distributions and vendors should prioritize patching and updating affected systems. Security teams and vulnerability management teams should verify affected versions and configurations, and implement additional security controls to limit the impact of

Why it matters

This vulnerability requires attention from Linux kernel developers and users of Linux-based systems that utilize Bluetooth RFCOMM functionality. The use-after-free condition can lead to potential system crashes or unexpected behavior, and may be exploited for malicious purposes. Verification of affected versions and application of patches is necessary to mitigate the risk.

• Potential system crashes or unexpected behavior due to use-after-free conditions.
• Possible elevation of privileges or unauthorized access to sensitive data.
• Increased risk of denial-of-service (DoS) attacks or other malicious activities.
• Need for verification of affected versions and application of patches.

Technical summary

The Linux kernel's Bluetooth RFCOMM implementation is vulnerable to a use-after-free condition due to a race between the installation and release of tty_port references. This can result in a potential crash or unexpected behavior. The vulnerability arises from a race condition between the installation and release of tty_port references, leading to a use-after-free condition when the release path drops the initial reference after the installation path has already dropped it. The issue can be addressed by using test_and_set_bit() in both paths so that only the caller that changes RFCOMM_TTY_OWNED from clear to set drops the initial reference.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided kernel patches to ensure the vulnerability is addressed.
• Monitor system logs for potential use-after-free errors related to the Bluetooth RFCOMM implementation.
• Consider implementing additional security controls, such as SELinux or AppArmor, to limit the impact of a potential exploit.
• Verify affected Linux kernel versions and configurations to determine exposure.
• Track and prioritize patching of affected systems based on criticality and exposure.
• Implement monitoring and detection controls to identify potential exploitation attempts.
• Conduct regular security audits and vulnerability assessments to identify and address potential weaknesses.

Evidence notes

The vulnerability was reported by an unspecified source and was resolved by the Linux kernel maintainers. The issue is caused by a race condition in the RFCOMM implementation, which can lead to a use-after-free condition.

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.