CVE-2022-41873 is a vulnerability identified in Contiki-NG, an open-source, cross-platform operating system designed specifically for next-generation Internet of Things (IoT) devices. The flaw exists in versions prior to 4.9 and involves an out-of-bounds read and write within the Bluetooth Low Energy (BLE) stack, specifically during the processing of the L2CAP protocol. The vulnerability arises in the function get_channel_for_cid located in the file os/net/mac/ble/ble-l2cap.c, which is responsible for mapping an incoming channel ID to its corresponding metadata structure. Although a bounds check is implemented to ensure the channel ID does not exceed the maximum supported channels, an integer truncation issue causes only the lowest byte of the channel ID to be validated. This incomplete check allows an attacker to supply a crafted channel ID that bypasses the bounds verification, leading to out-of-bounds memory access. Consequently, this can result in reading or writing memory outside the intended buffer, potentially corrupting memory or leaking sensitive information. The vulnerability is classified under CWE-125 (Out-of-bounds Read) and CWE-787 (Out-of-bounds Write). While no known exploits have been reported in the wild, the issue has been addressed in the development branch of Contiki-NG and is slated for inclusion in the upcoming 4.9 release. Users are advised to apply the patch available in pull request 2081 on GitHub as a workaround until the official release is available. This vulnerability is particularly critical in the context of IoT devices that rely on BLE communication, as exploitation could lead to device instability, data leakage, or unauthorized code execution depending on the device’s architecture and deployment context.

The impact of CVE-2022-41873 on European organizations primarily revolves around the security and reliability of IoT devices that utilize Contiki-NG as their operating system, especially those employing Bluetooth Low Energy communications. Given the widespread adoption of IoT devices in sectors such as manufacturing, smart cities, healthcare, and critical infrastructure across Europe, exploitation of this vulnerability could lead to several adverse outcomes. These include unauthorized access to sensitive data transmitted over BLE, potential disruption of device functionality through memory corruption, and in worst cases, the possibility of executing arbitrary code on the affected device. This could compromise the integrity and availability of critical IoT systems, leading to operational downtime, safety risks, and potential breaches of data protection regulations such as GDPR. Furthermore, since IoT devices often serve as entry points into larger networks, a compromised device could be leveraged as a pivot point for broader network intrusions. The medium severity rating reflects the need for vigilance but also acknowledges that exploitation requires crafted BLE packets and some technical sophistication. However, the pervasive deployment of IoT devices in European industries and public services elevates the risk profile, making timely mitigation essential to prevent cascading effects on organizational security and service continuity.

To effectively mitigate CVE-2022-41873, European organizations deploying Contiki-NG-based IoT devices should prioritize the following actions: 1) Immediate application of the patch from Contiki-NG pull request 2081 available on GitHub, even before the official 4.9 release, to address the integer truncation and bounds checking flaw. 2) Conduct a comprehensive inventory of all IoT devices running Contiki-NG to identify those with versions prior to 4.9, focusing on devices that utilize BLE communications. 3) Implement network segmentation and strict access controls for IoT devices to limit exposure to potentially malicious BLE traffic, including the use of BLE-specific intrusion detection systems where feasible. 4) Monitor BLE traffic for anomalous channel IDs or unusual patterns that could indicate attempts to exploit this vulnerability. 5) Collaborate with IoT device manufacturers and vendors to ensure firmware updates are applied promptly and to verify that devices are running patched versions. 6) Incorporate vulnerability scanning and penetration testing focused on BLE protocol handling within IoT environments to proactively identify exploitation attempts. 7) Educate operational technology (OT) and IT security teams about this specific vulnerability and the importance of securing BLE communications. These measures go beyond generic patching by emphasizing active monitoring, network controls, and organizational awareness tailored to the unique characteristics of IoT BLE stacks.