CVE-2024-46845 is a use-after-free vulnerability in the Linux kernel's timerlat tracer component, which is used to measure timer latency and OS noise by employing user space threads. The issue arises when a program using the timerlat tracer is terminated via SIGTERM. During shutdown, threads are closed sequentially, but if a new tracing instance starts before the old threads have fully shut down, it resets the threads prematurely. This leads to the high-resolution timer (hrtimer) associated with the kernel thread (kthread) being canceled and freed twice when the dying thread finally closes its file descriptors. This double-free scenario results in a use-after-free bug, which can cause kernel instability or potentially allow an attacker to execute arbitrary code or escalate privileges if exploited. The patch implemented addresses this by ensuring the hrtimer is only canceled if the associated kthread still exists and by adding an interface_lock to synchronize resetting the kthread pointer. However, this is a quick fix intended for backporting to stable kernels; a more robust fix would involve better synchronization between shutting down old threads and starting new ones. The vulnerability affects Linux kernel versions identified by specific commits (e88ed227f639ebcb31ed4e5b88756b47d904584b), and no known exploits are currently reported in the wild. The vulnerability does not have an assigned CVSS score yet.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with the affected timerlat tracer component enabled. The use-after-free bug can lead to kernel crashes, resulting in denial of service (DoS) conditions, which can disrupt critical infrastructure, enterprise servers, and cloud environments. More severe exploitation could allow attackers to execute arbitrary code within kernel space or escalate privileges, compromising system confidentiality and integrity. This is particularly concerning for sectors relying heavily on Linux-based systems such as finance, telecommunications, government, and critical infrastructure. The impact is heightened in environments where automated tracing and performance monitoring tools are used extensively, as these are more likely to invoke the vulnerable code path. Although no active exploits are known, the complexity of kernel vulnerabilities and their potential for severe impact necessitate prompt attention. Additionally, the quick fix nature of the patch suggests that organizations should monitor for further updates to ensure a comprehensive resolution.

European organizations should immediately apply the available patches or backported fixes for the Linux kernel to address CVE-2024-46845, ensuring that the timerlat tracer component is updated to prevent the use-after-free condition. System administrators should audit their environments to identify systems running affected kernel versions and verify if the timerlat tracer is in use. If the tracer is not required, disabling or avoiding its use can reduce exposure. Implementing strict process and thread management policies to avoid premature restarts of tracing instances can help mitigate race conditions leading to the vulnerability. Organizations should also monitor kernel logs for unusual crashes or errors related to hrtimer or kthread operations. Given the quick fix nature of the patch, it is advisable to stay informed about subsequent kernel updates that provide a more robust synchronization fix. Employing kernel live patching solutions where available can reduce downtime during patch deployment. Finally, incorporating this vulnerability into vulnerability management and incident response plans will ensure timely detection and remediation.