CVE-2022-49909 is a use-after-free (UAF) vulnerability in the Linux kernel's Bluetooth subsystem, specifically within the L2CAP (Logical Link Control and Adaptation Protocol) layer. The flaw arises in the handling of the A2MP (Alternate MAC/PHY Manager Protocol) channel creation and deletion processes. When the kernel receives data via l2cap_recv_frame() with a channel identifier (cid) of L2CAP_CID_A2MP, it may create a new channel if one does not exist. However, the reference counting for this channel is mishandled: after creation, the channel's hold operation is not properly performed, leaving the reference count at 1 instead of a safer higher value. Subsequently, when an error reset event (hci_error_reset()) occurs, the channel is closed and freed prematurely. The l2cap_conn_del() function calls the close hook for A2MP, which releases the channel and reduces the reference count to zero, freeing the memory. Immediately after, l2cap_chan_unlock() attempts to unlock the channel, which has already been freed, causing a use-after-free condition. This vulnerability is detected by Kernel Address Sanitizer (KASAN) as an invalid memory access during mutex unlock operations. The issue can lead to kernel crashes or potential arbitrary code execution in kernel space if exploited. The vulnerability affects multiple Linux kernel versions identified by specific commit hashes and was publicly disclosed on May 1, 2025. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a significant risk to systems running vulnerable Linux kernel versions with Bluetooth enabled, especially those using Bluetooth for critical communications or device management. Exploitation could lead to kernel crashes (denial of service), potentially disrupting services and operations. More critically, a successful exploit might allow an attacker to execute arbitrary code with kernel privileges, compromising system confidentiality, integrity, and availability. This is particularly concerning for sectors relying on Linux-based embedded systems, IoT devices, or industrial control systems that utilize Bluetooth connectivity. The vulnerability could be leveraged in targeted attacks against enterprise infrastructure, telecommunications equipment, or critical infrastructure components. Given the widespread use of Linux in European data centers, government agencies, and enterprises, the impact could be broad if patches are not applied promptly.

European organizations should prioritize updating their Linux kernel to versions where this vulnerability is patched. Since no direct patch links are provided, organizations should monitor official Linux kernel repositories and distributions for updates addressing CVE-2022-49909. In environments where immediate patching is not feasible, disabling Bluetooth functionality or restricting Bluetooth usage to trusted devices can reduce attack surface. Additionally, implementing kernel hardening techniques such as enabling Kernel Address Sanitizer (KASAN) in testing environments can help detect similar issues early. Network segmentation and strict access controls around Bluetooth-enabled devices can limit potential exploitation. Organizations should also audit and monitor kernel logs for unusual Bluetooth-related errors or crashes that might indicate exploitation attempts. Finally, maintaining up-to-date intrusion detection systems with signatures for kernel-level anomalies can aid in early detection.