CVE-2022-49138 is a vulnerability identified in the Linux kernel's Bluetooth subsystem, specifically within the handling of HCI (Host Controller Interface) events. The flaw arises when multiple 'connection complete' events are received for the same connection handle. Normally, a single connection complete event signals the successful establishment of a Bluetooth connection. However, if the system processes multiple such events for the same handle, it results in the device being registered multiple times. This erroneous behavior leads to memory corruption within the kernel. To address this, the Linux kernel developers introduced a new constant, HCI_CONN_HANDLE_UNSET, to clearly identify new connections and prevent reuse of invalid or duplicate handles. Additionally, upper bounds checks using HCI_CONN_HANDLE_MAX were implemented to validate event handles and prevent invalid values from causing further issues. The vulnerability is rooted in improper state management and event validation in the Bluetooth HCI event processing code. Although no known exploits are currently reported in the wild, the underlying memory corruption could potentially be leveraged by an attacker to cause denial of service or escalate privileges if exploited. The vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, and was publicly disclosed on February 26, 2025. No CVSS score has been assigned yet, and no patches or exploit code links are provided in the initial disclosure. The bug report is available at the Linux kernel bugzilla page (https://bugzilla.kernel.org/show_bug.cgi?id=215497).

For European organizations, the impact of CVE-2022-49138 depends largely on the extent to which Linux-based systems with Bluetooth capabilities are deployed, particularly in critical infrastructure, enterprise environments, and embedded devices. Memory corruption vulnerabilities in the kernel can lead to system instability, crashes, or potentially privilege escalation if exploited, which could compromise confidentiality, integrity, and availability of affected systems. Organizations using Linux servers, workstations, or IoT devices with Bluetooth enabled may face risks of denial of service or unauthorized code execution. Given the kernel-level nature of the vulnerability, successful exploitation could allow attackers to bypass security controls or gain kernel-level privileges. This is particularly concerning for sectors such as manufacturing, healthcare, and telecommunications, where Linux-based embedded systems and Bluetooth connectivity are common. However, the lack of known exploits and the requirement for Bluetooth interaction somewhat limit the attack surface. Still, the vulnerability could be leveraged in targeted attacks against devices with exposed or accessible Bluetooth interfaces, especially in environments where physical proximity or network access to Bluetooth devices is feasible.

European organizations should prioritize updating their Linux kernel versions to include the fix for CVE-2022-49138 as soon as patches become available from their Linux distribution vendors. Until patches are applied, organizations should consider disabling Bluetooth functionality on Linux systems where it is not essential, especially on servers and critical infrastructure devices. For devices requiring Bluetooth, implementing strict access controls and monitoring Bluetooth activity can help detect anomalous connection attempts. Network segmentation to isolate Bluetooth-enabled devices and restricting physical access to such devices can reduce exploitation risk. Additionally, organizations should audit their Linux systems to identify all devices with Bluetooth enabled and verify kernel versions to assess exposure. Employing intrusion detection systems capable of monitoring kernel-level anomalies and memory corruption indicators can provide early warning. Finally, maintaining up-to-date asset inventories and ensuring rapid patch management processes will help mitigate risks from this and similar kernel vulnerabilities.