CVE-2022-49659 addresses a vulnerability in the Linux kernel's CAN (Controller Area Network) subsystem, specifically within the m_can driver that handles CAN peripheral devices. The issue stems from the handling of timestamps associated with received CAN frames. In the Linux kernel commit 1be37d3b0414, the RX path for peripheral CAN devices was modified to use RX-offload, a mechanism designed to process received packets in a softirq context to improve performance and reliability. RX-offload expects timestamps to be 32 bits wide to correctly handle timestamp overflows. However, the m_can core originally provided only 16-bit timestamps, which could lead to incorrect timestamp handling when passed to RX-offload. This discrepancy could cause improper processing of CAN frames, potentially affecting the timing and ordering of messages. The patch for this vulnerability shifts the 16-bit timestamps to full 32-bit values before passing them to RX-offload, ensuring correct overflow handling and maintaining the integrity of CAN frame processing. While the vulnerability does not directly indicate a memory corruption or privilege escalation, incorrect timestamp handling in CAN communication could lead to subtle data integrity issues or timing-related faults in systems relying on CAN for critical communication, such as automotive or industrial control systems running Linux kernels with the affected m_can driver versions.

For European organizations, particularly those in automotive manufacturing, industrial automation, and critical infrastructure sectors that utilize Linux-based systems with CAN interfaces, this vulnerability could impact the reliability and integrity of CAN communications. CAN is widely used in automotive ECUs and industrial control systems, where precise timing and message ordering are crucial. Incorrect timestamp handling could lead to misinterpretation of CAN frames, potentially causing system malfunctions or degraded performance. While no direct exploitation or remote attack vector is indicated, the vulnerability could affect safety-critical systems if left unpatched, leading to operational disruptions or safety risks. European automotive manufacturers and suppliers, as well as industrial operators using Linux-based CAN devices, could face increased risk of system instability or failures if this vulnerability is not addressed.

To mitigate this vulnerability, organizations should ensure that Linux kernel versions deployed on systems using CAN peripherals are updated to include the patch that shifts timestamps to 32 bits before passing them to RX-offload. Specifically, kernel versions incorporating commit 1be37d3b0414 or later should be deployed. System integrators and administrators should audit their Linux kernel versions and apply vendor-provided security updates promptly. Additionally, thorough testing of CAN communication functionality after patching is recommended to verify correct timestamp handling and system stability. For embedded or custom Linux distributions, recompiling the kernel with the patched m_can driver is necessary. Monitoring CAN bus traffic for anomalies or timing inconsistencies can also help detect potential issues related to this vulnerability. Finally, organizations should maintain rigorous change management and update policies for embedded Linux systems in automotive and industrial environments to prevent exposure to similar low-level kernel vulnerabilities.