CVE-2022-49136 is a high-severity vulnerability affecting the Linux kernel's Bluetooth subsystem, specifically within the hci_sync command queue handling. The issue arises when the hci_cmd_sync_queue function does not properly handle the HCI_UNREGISTER flag. This flag indicates that the Bluetooth device has been unregistered via hci_unregister_dev, meaning the associated device structure (hdev) is freed. If commands continue to be queued after this unregistration, it can lead to a use-after-free (UAF) condition. This UAF vulnerability can cause memory corruption, potentially allowing an attacker to execute arbitrary code with kernel privileges or cause a denial of service by crashing the kernel. The vulnerability is identified as CWE-416 (Use After Free). Exploitation requires local access (AV:L), low complexity (AC:L), and low privileges (PR:L), but no user interaction (UI:N). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No known exploits are currently reported in the wild. The vulnerability was addressed by modifying the hci_cmd_sync_queue function to return an error if the HCI_UNREGISTER flag is set, preventing commands from being queued after device unregistration and thus avoiding the UAF condition.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Linux-based systems with Bluetooth capabilities, such as servers, embedded devices, IoT infrastructure, and workstations. Successful exploitation could lead to kernel-level code execution, compromising system confidentiality, integrity, and availability. This could result in unauthorized access to sensitive data, disruption of critical services, or lateral movement within networks. Given the widespread use of Linux in enterprise environments and critical infrastructure across Europe, the vulnerability could impact sectors including telecommunications, manufacturing, healthcare, and government. The requirement for local access lowers the risk of remote exploitation but raises concerns for insider threats or compromised endpoints within secure networks. The lack of known exploits in the wild suggests that proactive patching can effectively mitigate risk before active attacks emerge.

European organizations should prioritize updating Linux kernel versions to include the patch that addresses CVE-2022-49136. Specifically, ensure that all systems running Bluetooth-enabled Linux kernels are upgraded to versions where hci_cmd_sync_queue properly checks the HCI_UNREGISTER flag. Additionally, organizations should: 1) Audit and restrict local user privileges to minimize the risk of exploitation by low-privilege users. 2) Implement strict access controls and monitoring on devices with Bluetooth capabilities to detect anomalous command queuing or device unregistration events. 3) Disable Bluetooth on Linux systems where it is not required to reduce the attack surface. 4) Employ kernel integrity monitoring tools to detect unusual behavior indicative of exploitation attempts. 5) Maintain up-to-date asset inventories to identify all affected systems promptly. These measures, combined with patch management, will reduce the likelihood and impact of exploitation.