CVE-2024-36011 is a medium-severity vulnerability identified in the Linux kernel's Bluetooth subsystem, specifically within the Host Controller Interface (HCI) layer. The flaw involves a potential null pointer dereference in the function hci_le_big_sync_established_evt(), which handles Bluetooth Low Energy (LE) BIG (Broadcast Isochronous Group) synchronization established events. A null pointer dereference occurs when the code attempts to access or manipulate memory through a pointer that has not been properly initialized or has been set to null, leading to a kernel crash or denial of service (DoS). This vulnerability does not impact confidentiality or integrity but affects availability by potentially causing the kernel to panic or crash when processing crafted Bluetooth LE BIG synchronization events. The CVSS 3.1 base score is 5.5 (medium), with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring low privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), no confidentiality or integrity impact (C:N/I:N), and high availability impact (A:H). Exploitation requires local access with Bluetooth capabilities and some privileges but no user interaction, making it moderately accessible to attackers with local system access. No known exploits are reported in the wild as of the publication date (May 23, 2024). The vulnerability is addressed by patches in the Linux kernel source code, although no direct patch links were provided in the data. The underlying weakness is classified under CWE-476 (NULL Pointer Dereference).

For European organizations, this vulnerability primarily poses a risk of denial of service on Linux systems that utilize Bluetooth LE BIG features, which are common in modern Linux distributions used in enterprise environments, embedded systems, and IoT devices. A successful exploit could cause system instability or crashes, disrupting critical services, especially in environments relying on Bluetooth connectivity for device communication or control (e.g., manufacturing, healthcare, or logistics). While it does not allow data theft or privilege escalation, the availability impact could lead to operational downtime and potential safety risks in industrial or medical settings. Organizations with extensive Linux deployments, particularly those using Bluetooth-enabled devices or applications, may experience service interruptions or require emergency patching. The lack of known exploits reduces immediate risk but does not eliminate the need for prompt remediation to prevent future exploitation.

European organizations should prioritize updating their Linux kernel versions to incorporate the fix for CVE-2024-36011 as soon as vendor patches become available. In the interim, administrators can mitigate risk by disabling Bluetooth functionality on systems where it is not essential, especially on critical infrastructure servers or embedded devices. For systems requiring Bluetooth, monitoring kernel logs for unusual Bluetooth HCI events or crashes can help detect attempted exploitation. Employing strict access controls to limit local user privileges and restricting physical or remote access to systems with Bluetooth capabilities reduces the attack surface. Additionally, organizations should ensure their incident response and patch management processes are prepared to rapidly deploy kernel updates. For embedded or IoT devices running custom Linux kernels, vendors should be engaged to provide updated firmware incorporating the patch. Network segmentation can also limit the impact of compromised devices. Finally, maintaining up-to-date inventory of Bluetooth-enabled Linux systems aids in targeted remediation efforts.