CVE-2024-44962 is a vulnerability identified in the Linux kernel specifically affecting the Bluetooth btnxpuart driver. The issue arises during the unloading process of the btnxpuart driver, where its associated shutdown timer is deleted improperly. If the timer is modified concurrently at the moment of driver unloading, the kernel may still invoke this timer callback even after the driver has been unloaded. This results in a use-after-free condition leading to a kernel panic, causing a denial of service (DoS) by crashing the system. The root cause is the use of del_timer_sync() to delete the timer, which does not prevent the timer from being rearmed during the deletion process. The fix involves replacing del_timer_sync() with timer_shutdown_sync(), which ensures the timer is shut down synchronously and cannot be rearmed after the driver unload begins. The panic logs indicate an internal kernel error triggered by a fatal exception in interrupt context, with the kernel stopping secondary CPUs and halting system operation. This vulnerability affects Linux kernel versions containing the vulnerable btnxpuart driver implementation, including embedded systems such as those running on NXP i.MX95 hardware. Although no known exploits are currently reported in the wild, the vulnerability can be triggered locally or remotely if an attacker can cause the driver to unload while manipulating the timer, leading to system instability or crash. This vulnerability is particularly relevant for systems relying on Bluetooth connectivity with the btnxpuart driver, including IoT devices, embedded Linux platforms, and potentially desktop or server systems using affected kernel versions.

For European organizations, the impact of CVE-2024-44962 primarily involves system availability and reliability. Systems running vulnerable Linux kernels with the btnxpuart Bluetooth driver may experience kernel panics and crashes, resulting in denial of service. This can disrupt critical operations, especially in industrial, telecommunications, and embedded device environments where Linux is prevalent. Organizations using embedded Linux devices in manufacturing, automotive, or healthcare sectors could face operational downtime or require costly reboots and maintenance. While the vulnerability does not directly expose confidentiality or integrity risks, the resulting system instability can indirectly affect business continuity and safety-critical processes. Additionally, if attackers can remotely trigger the driver unload and timer manipulation, this could be leveraged as a vector for targeted disruption attacks. European organizations with large deployments of Linux-based IoT or embedded systems should be particularly vigilant, as these devices often have limited patching capabilities and may be exposed to local or network-based exploitation attempts. The lack of known exploits in the wild reduces immediate risk but does not eliminate the potential for future weaponization.

1. Apply the official Linux kernel patch that replaces del_timer_sync() with timer_shutdown_sync() in the btnxpuart driver to ensure proper timer shutdown and prevent rearming during driver unload. 2. Update all affected Linux kernel versions to the latest stable releases containing this fix as soon as possible, especially on embedded and IoT devices. 3. For devices where kernel updates are challenging, consider disabling or unloading the btnxpuart Bluetooth driver if Bluetooth functionality is not required. 4. Implement monitoring for kernel panics and system crashes related to Bluetooth driver activity to detect potential exploitation attempts early. 5. Restrict local user privileges to prevent unauthorized unloading of kernel modules or manipulation of Bluetooth drivers. 6. For network-exposed devices, employ network segmentation and firewall rules to limit access to Bluetooth management interfaces and reduce attack surface. 7. Coordinate with device vendors and embedded system manufacturers to ensure timely firmware and kernel updates addressing this vulnerability. 8. Conduct thorough testing of kernel updates in controlled environments before deployment to avoid regressions in embedded systems.