CVE-2024-46755 is a vulnerability identified in the Linux kernel's mwifiex wireless driver component. The flaw arises from the function mwifiex_get_priv_by_id(), which is responsible for returning a private data pointer (priv) corresponding to specific BSS (Basic Service Set) identifiers such as bss_num and bss_type. The vulnerability occurs because the function does not verify whether the returned priv pointer is currently in use. Specifically, unused priv pointers lack an associated wiphy (wireless physical device) structure, which leads to a NULL pointer dereference when subsequent kernel code attempts to access wiphy-related data. This NULL pointer dereference can cause a kernel oops or crash, resulting in denial of service (DoS) conditions. The issue manifests when an access point is started using wpa_supplicant with a particular configuration, and the process is interrupted and restarted, triggering the dereference. The kernel logs show an inability to handle the NULL pointer dereference, with detailed stack traces pointing to the mwifiex_get_cfp() function and related event processing routines within the mwifiex driver. The root cause is that mwifiex_get_priv_by_id() returns priv pointers without checking if priv->bss_mode is set to a valid mode other than NL80211_IFTYPE_UNSPECIFIED, which indicates an unused interface. The fix involves modifying mwifiex_get_priv_by_id() to return only priv pointers that are actively in use, thus preventing NULL pointer dereferences downstream. This vulnerability affects Linux kernel versions containing the vulnerable mwifiex driver code prior to the patch. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with the vulnerable mwifiex wireless driver, especially those using wireless access points or client devices relying on mwifiex for Wi-Fi connectivity. The impact is mainly a denial of service condition caused by kernel crashes due to NULL pointer dereferences. This can disrupt network connectivity, degrade service availability, and potentially cause system instability or require reboots. Critical infrastructure, enterprises, and service providers using embedded Linux devices or IoT equipment with mwifiex-based Wi-Fi modules could experience operational interruptions. While the vulnerability does not directly lead to privilege escalation or remote code execution, the resulting DoS could be leveraged in targeted attacks to disrupt services or cause outages. Given the widespread use of Linux in servers, networking equipment, and embedded devices across Europe, the vulnerability could affect a broad range of sectors including telecommunications, manufacturing, and public services. However, exploitation requires specific conditions such as starting/stopping access points with wpa_supplicant and interrupting processes, which somewhat limits the attack surface to local or administrative users.

European organizations should prioritize updating their Linux kernel versions to include the patch that fixes the mwifiex_get_priv_by_id() function to properly validate priv pointers. For embedded devices or appliances where kernel updates are not immediately feasible, consider disabling or restricting the use of mwifiex wireless interfaces if they are not essential. Network administrators should monitor logs for kernel oops or crashes related to mwifiex and implement process controls to avoid interrupting wpa_supplicant or similar services in a manner that triggers the vulnerability. Additionally, applying strict access controls to limit who can start or stop wireless interfaces reduces the risk of accidental or malicious triggering. Organizations should also conduct audits of devices using mwifiex drivers to identify vulnerable systems and plan for timely patch deployment. Employing kernel crash monitoring and automated recovery mechanisms can help mitigate operational impact. Finally, vendors and integrators should be engaged to ensure firmware and kernel updates are delivered promptly for affected hardware platforms.