CVE-2024-41023 is a vulnerability identified in the Linux kernel's real-time scheduling subsystem, specifically within the deadline scheduler code. The flaw involves a reference count leak of the task_struct data structure, which represents processes in the kernel. The issue arises in the start_dl_timer() function, which increments the reference count of a task_struct and sets a timer. The timer's callback, dl_task_timer, is responsible for decrementing this reference count when the timer expires. However, if the function enqueue_task_dl() is invoked before the timer expires and cancels the timer, the reference count decrement does not occur, causing a reference leak. This leak means the kernel holds onto task_struct objects longer than necessary, leading to a memory leak. The vulnerability was discovered during stress testing with linux-rt using stress-ng, where kmemleak detected unreferenced task_struct objects that were not freed properly. The patch for this vulnerability ensures that when the timer is canceled, the task_struct reference count is correctly decremented, preventing the leak. While this vulnerability does not directly enable code execution or privilege escalation, the memory leak can degrade system stability and performance over time, especially under heavy load or real-time scheduling conditions. The flaw affects specific Linux kernel versions identified by their commit hashes, and it is relevant to systems using the Linux real-time kernel patches or configurations that utilize the deadline scheduler.

For European organizations, the impact of CVE-2024-41023 primarily concerns systems running Linux kernels with real-time scheduling enabled, such as those used in industrial control systems, telecommunications infrastructure, embedded devices, and critical real-time applications. The memory leak caused by the reference count issue can lead to gradual exhaustion of kernel memory resources, potentially resulting in system slowdowns, degraded performance, or even kernel crashes if the leak is severe and sustained. This can disrupt critical services, especially in sectors relying on real-time Linux kernels for deterministic behavior, such as manufacturing automation, energy grid management, and transportation systems. While the vulnerability does not appear to facilitate direct exploitation for privilege escalation or remote code execution, the resulting instability could be leveraged by attackers as part of a denial-of-service strategy. European organizations with high availability requirements and those operating critical infrastructure should be particularly vigilant. Additionally, the leak could complicate forensic analysis and system monitoring by obscuring resource usage patterns. Given the widespread use of Linux across European enterprises and public sector entities, the vulnerability poses a moderate operational risk if unpatched in relevant environments.

To mitigate CVE-2024-41023, European organizations should prioritize applying the official Linux kernel patches that fix the reference count leak in the deadline scheduler. This involves updating to the latest stable or real-time kernel versions that include the fix. For environments where immediate patching is not feasible, organizations should monitor kernel memory usage closely, especially under workloads involving real-time scheduling or stress testing with tools like stress-ng. Implementing kernel memory leak detection tools such as kmemleak can help identify if the issue is present in their systems. Additionally, organizations should review and limit the use of real-time scheduling features to only necessary workloads to reduce exposure. For embedded or specialized devices using custom Linux kernels, vendors should be engaged to provide patched firmware updates. Finally, system administrators should ensure robust system monitoring and alerting to detect early signs of resource exhaustion or instability that could be symptomatic of this leak.