CVE-2024-46771 is a vulnerability in the Linux kernel's CAN (Controller Area Network) BCM (Broadcast Manager) socket implementation. The issue arises from improper cleanup of proc filesystem entries when a bound network device is unregistered. Specifically, when a BCM socket calls connect(), it allocates a proc entry to represent the socket state. The bcm_sk(sk)->bound flag is set to prevent multiple connects. However, if the bound device is removed, bcm_notify() resets this bound flag to zero. This allows a second connect() call to allocate a proc entry with the same name without properly releasing the original proc entry, leading to a resource leak. The vulnerability was discovered via syzkaller, a kernel fuzzer, which triggered a warning about duplicate proc entries. The root cause is that the proc entry is only cleaned up during connect() but not when the network device is unregistered, causing dangling proc entries and potential resource exhaustion. The vulnerability affects Linux kernel versions prior to the patch that ensures proc entries are removed when the bound net device is unregistered. The kernel stack trace and error messages indicate the problem occurs in proc_register() and bcm_connect() functions. While the vulnerability does not appear to allow direct code execution or privilege escalation, the leaking of proc entries can lead to resource exhaustion or denial of service (DoS) conditions on affected systems. No known exploits are currently reported in the wild. The vulnerability is specific to systems using CAN BCM sockets, which are commonly used in automotive and industrial control environments for communication over CAN networks.

For European organizations, the impact of CVE-2024-46771 depends largely on the deployment of Linux systems utilizing CAN BCM sockets. Industries such as automotive manufacturing, industrial automation, and embedded systems development are more likely to use CAN interfaces. A successful exploitation could lead to denial of service by exhausting kernel resources through proc entry leaks, potentially disrupting critical communication channels in automotive or industrial control systems. This could affect manufacturing lines, vehicle diagnostics, or embedded device operations. While the vulnerability does not directly expose confidential data or allow privilege escalation, the resulting instability or crashes could impact operational continuity and safety-critical systems. European organizations with embedded Linux devices or automotive testing infrastructure should be particularly vigilant. The vulnerability is less likely to affect general-purpose Linux servers or desktops that do not use CAN BCM sockets. However, given the strategic importance of automotive and industrial sectors in Europe, the risk of disruption is non-negligible.

To mitigate CVE-2024-46771, organizations should apply the official Linux kernel patches that ensure proc entries are properly removed when the bound network device is unregistered. This fix prevents resource leaks and stabilizes BCM socket behavior. In environments where immediate patching is not feasible, administrators should monitor kernel logs for warnings related to proc entry duplication or bcm_connect failures as early indicators of exploitation attempts. Limiting access to CAN BCM sockets to trusted users and processes reduces the risk of triggering the vulnerability. Additionally, implementing resource limits on proc filesystem usage and socket creation can help contain potential resource exhaustion. For embedded or automotive systems, firmware updates incorporating the patched kernel version should be prioritized. Network segmentation and strict access controls around devices using CAN interfaces further reduce exposure. Regular auditing of kernel versions and vulnerability advisories is recommended to ensure timely application of security updates.