CVE-2024-36932 is a use-after-free vulnerability identified in the Linux kernel's thermal debugging subsystem. Specifically, the issue arises in the interaction between thermal_debug_cdev_remove() and thermal_debug_cdev_state_update() functions. The root cause is that thermal_debug_cdev_remove() does not acquire the cdev->lock mutex when removing the character device (cdev) and resetting its debugfs pointer to NULL. This lack of synchronization allows a race condition where thermal_debug_cdev_state_update() can concurrently access the thermal_debugfs structure after it has been freed by thermal_debug_cdev_remove(). Since thermal_debug_cdev_state_update() only checks if the pointer is NULL but does not hold the lock, it may dereference a pointer to freed memory, leading to a kernel crash (denial of service). The vulnerability affects Linux kernel versions starting from commit 755113d7678681a137c330f7997ceb680adb644e and later. The fix involves adding proper locking (cdev->lock) around the critical section in thermal_debug_cdev_remove() to ensure that the debugfs pointer is safely checked and reset, preventing concurrent access to freed memory. This vulnerability is a classic use-after-free bug that can cause system instability and crashes but does not appear to allow privilege escalation or arbitrary code execution directly. There are no known exploits in the wild as of the publication date (May 30, 2024), and no CVSS score has been assigned yet.

For European organizations, the primary impact of CVE-2024-36932 is the potential for denial of service due to kernel crashes on Linux systems that utilize the affected thermal debugging features. This could disrupt critical services, especially in environments running Linux kernels with the vulnerable code, such as servers, embedded devices, or workstations used in industrial control, telecommunications, or cloud infrastructure. While the vulnerability does not directly lead to data breaches or privilege escalation, repeated crashes could cause operational downtime, data loss from interrupted processes, and increased maintenance costs. Organizations relying on Linux-based infrastructure for critical operations may face reduced availability and reliability until patches are applied. The impact is more pronounced in environments where thermal debugging is enabled or where concurrent device removal and state updates occur, such as in complex hardware monitoring setups or development environments.

To mitigate CVE-2024-36932, European organizations should: 1) Identify Linux systems running kernel versions from commit 755113d7678681a137c330f7997ceb680adb644e onward and verify if thermal debugging features are enabled. 2) Apply the official Linux kernel patches that introduce proper locking in thermal_debug_cdev_remove() as soon as they become available through vendor updates or mainline kernel releases. 3) If immediate patching is not possible, consider disabling thermal debugfs interfaces temporarily to reduce the attack surface, especially on production systems. 4) Monitor system logs for kernel crashes or oops messages related to thermal debugging to detect potential exploitation attempts or instability. 5) Implement robust system monitoring and automated reboot mechanisms to minimize downtime caused by unexpected kernel crashes. 6) Coordinate with hardware and Linux distribution vendors to ensure timely updates and verify that custom kernels used in embedded or specialized devices incorporate the fix.