CVE-2024-42279 is a vulnerability identified in the Linux kernel's SPI (Serial Peripheral Interface) microchip-core driver. The issue arises during SPI data transfers when the receive length (rx_len) is zero. In this scenario, the RX FIFO (First-In-First-Out buffer) is not cleared in the interrupt handler before a new transfer begins. As a result, residual data from a previous transfer may remain in the RX FIFO and subsequently be read into the RX buffer of the new transfer. This can lead to the new transfer receiving stale or corrupted data, potentially causing data integrity issues or unexpected behavior in applications relying on SPI communication. The root cause is that the driver fails to empty the RX and TX FIFOs at the start of each transfer, despite the hardware providing a register to perform this clearing operation. The vulnerability has been addressed by ensuring that both the TX and RX FIFOs are emptied before each SPI transfer, preventing the carryover of old data. This fix improves the reliability and correctness of SPI communications handled by the Linux kernel microchip-core driver. No known exploits are reported in the wild at this time, and the vulnerability was published on August 17, 2024. The affected versions are specific Linux kernel commits identified by the hash 9ac8d17694b66d54b13e9718b25c14ca36dbebbd. No CVSS score has been assigned yet.

For European organizations, this vulnerability primarily affects systems that rely on Linux-based devices using the microchip-core SPI driver for communication with peripherals. This includes embedded systems, industrial control systems, IoT devices, and potentially networking equipment that use SPI interfaces for sensor data, configuration, or control signals. The impact is mainly on data integrity and reliability of SPI communications, which could lead to incorrect data processing, system malfunctions, or degraded operational performance. While this vulnerability does not directly lead to remote code execution or privilege escalation, corrupted data transfers could disrupt critical functions in industrial environments or embedded applications, potentially causing downtime or safety issues. Organizations in sectors such as manufacturing, automotive, telecommunications, and critical infrastructure that deploy Linux-based embedded systems are most at risk. Since no known exploits exist yet, the immediate risk is low, but the vulnerability should be addressed promptly to prevent future exploitation or operational issues.

To mitigate CVE-2024-42279, European organizations should: 1) Apply the official Linux kernel patches that ensure the TX and RX FIFOs are cleared before each SPI transfer, as provided by the Linux kernel maintainers. 2) Identify and inventory all Linux-based systems and embedded devices using the microchip-core SPI driver, prioritizing those in critical operational roles. 3) Test updated kernel versions in controlled environments to verify that SPI communications are stable and that the fix does not introduce regressions. 4) For devices where kernel updates are not immediately feasible, consider implementing additional application-level validation or error checking on SPI data to detect corrupted or stale data. 5) Monitor vendor advisories and firmware updates for embedded devices that may incorporate this kernel fix. 6) Incorporate this vulnerability into vulnerability management and patching workflows to ensure timely remediation. 7) Educate development and operations teams about the importance of SPI data integrity and the potential impacts of this vulnerability in embedded Linux environments.