CVE-2024-27408 is a vulnerability identified in the Linux kernel's DMA engine (dmaengine) subsystem, specifically within the DesignWare eDMA (dw-edma) controller implementation. The issue arises from a race condition related to the handling of linked list elements and pointers used to control DMA transfers. In this context, the linked list element and pointer are stored separately from the eDMA controller registers. The vulnerability occurs because the doorbell register, which signals the start of a DMA transfer, can be toggled before the complete write of the linked list data has been finalized in memory. This premature toggling can lead to inconsistent or partial data being used by the DMA controller, causing a race condition error. The root cause is that the system does not ensure memory synchronization before starting the DMA transfer. The fix involves adding a synchronous read (readl) operation to the memory location to guarantee that the full write of the linked list has been completed before the doorbell register is toggled to start the DMA operation. This synchronization prevents the race condition by ensuring memory consistency between the CPU and the DMA controller. The vulnerability affects specific versions of the Linux kernel identified by their commit hashes, indicating it is present in certain recent kernel builds prior to the fix. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet. The vulnerability is technical and low-level, impacting the kernel's DMA engine functionality, which is critical for efficient data transfers between memory and peripherals without CPU intervention.

For European organizations, this vulnerability could have significant implications depending on their use of Linux-based systems that rely on the DesignWare eDMA controller for DMA operations. The race condition could lead to data corruption, system instability, or unexpected behavior in devices that perform DMA transfers, potentially affecting critical infrastructure, embedded systems, or industrial control systems running Linux kernels with the vulnerable code. While there is no evidence of active exploitation, the vulnerability could be leveraged by attackers with local access or through malicious code execution to disrupt system operations or cause denial of service. This is particularly relevant for sectors such as manufacturing, telecommunications, automotive, and IoT deployments prevalent in Europe, where embedded Linux systems are common. The impact on confidentiality is limited since this is primarily a race condition affecting data integrity and availability. However, if exploited, it could lead to system crashes or unpredictable device behavior, impacting operational continuity and reliability. Organizations relying on Linux kernel versions containing this vulnerability should consider the risk to their embedded and industrial systems, especially those with real-time or safety-critical requirements.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernel to versions where the patch for CVE-2024-27408 has been applied. This involves applying the kernel patch that introduces the synchronous read (readl) operation before starting DMA transfers to ensure memory write completion. For embedded and industrial systems where kernel updates may be challenging, organizations should work with their hardware and software vendors to obtain patched firmware or kernel versions. Additionally, organizations should audit their systems to identify devices and applications using the DesignWare eDMA controller and assess their exposure. Implementing strict access controls to limit local user privileges can reduce the risk of exploitation, as the vulnerability requires local code execution or privileged access to trigger the race condition. Monitoring system logs for unusual DMA-related errors or crashes may help detect attempts to exploit the vulnerability. Finally, organizations should incorporate this vulnerability into their vulnerability management and patching cycles, ensuring timely deployment of fixes and validation in test environments before production rollout.