CVE-2024-50255 is a vulnerability identified in the Linux kernel's Bluetooth subsystem, specifically within the handling of HCI (Host Controller Interface) commands. The flaw arises in the function __hci_cmd_sync_sk(), which is responsible for synchronously sending HCI commands and waiting for their completion. The vulnerability occurs because this function returns NULL not only when a command returns a status event but also when an opcode is not found in the hci_cc command completion table. This behavior leads to a null pointer dereference in the hci_read_supported_codecs() function when it attempts to process the HCI_OP_READ_LOCAL_CODECS opcode, which is not present in the hci_cc table. The assumption that the status byte is always present at skb->data[0] for unknown opcodes causes the kernel to dereference a NULL pointer, resulting in a kernel crash (null pointer dereference). The issue was detected with Kernel Address Sanitizer (KASAN) and affects Linux kernel version 6.9.0 and potentially others with similar Bluetooth HCI implementations. The stack trace shows the problem occurs during Bluetooth device initialization and codec reading phases, which are critical for Bluetooth functionality. This vulnerability can cause denial of service (DoS) by crashing the kernel when the affected Bluetooth commands are processed. There is no indication of remote code execution or privilege escalation directly from this flaw, but the kernel crash can disrupt system availability and Bluetooth-dependent services. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-50255 primarily involves potential denial of service conditions on Linux systems utilizing Bluetooth functionality. Many enterprises and public sector entities in Europe rely on Linux-based infrastructure, including servers, desktops, and embedded devices that support Bluetooth communication. A kernel crash triggered by this vulnerability could disrupt critical operations, especially in environments where Bluetooth is used for device pairing, secure access, or IoT device management. Industrial control systems, healthcare devices, and transportation systems that run Linux and use Bluetooth could experience outages or degraded service. The disruption could affect confidentiality indirectly if system availability impacts security monitoring or incident response capabilities. Integrity is less likely to be affected as this is not a code execution vulnerability. Availability impact is moderate to high depending on the reliance on Bluetooth services. Since exploitation requires triggering specific Bluetooth HCI commands, attackers with local access or the ability to send crafted Bluetooth commands could cause system crashes. This risk is heightened in environments with many Bluetooth-enabled devices or where attackers can connect to Bluetooth interfaces. European organizations with large Linux deployments, especially those in technology, manufacturing, healthcare, and critical infrastructure sectors, should be aware of this threat.

To mitigate CVE-2024-50255, European organizations should: 1) Apply the latest Linux kernel patches as soon as they become available from trusted sources or distributions, ensuring the fix for the null pointer dereference in the Bluetooth HCI code is included. 2) Temporarily disable Bluetooth functionality on critical systems where it is not essential, reducing the attack surface until patches are applied. 3) Implement strict access controls on Bluetooth interfaces, including disabling Bluetooth on servers and devices where it is unnecessary or restricting pairing and connection capabilities to trusted devices only. 4) Monitor kernel logs and system behavior for signs of crashes or Bluetooth subsystem errors that may indicate attempted exploitation. 5) For embedded or IoT devices running Linux with Bluetooth, coordinate with vendors to obtain firmware updates or patches addressing this vulnerability. 6) Employ network segmentation and endpoint protection to limit attacker access to systems with Bluetooth interfaces. 7) Educate system administrators about this vulnerability and the importance of timely patching and Bluetooth management. These steps go beyond generic advice by focusing on controlling Bluetooth access and monitoring kernel stability related to Bluetooth operations.