CVE-2024-56557 is a medium-severity vulnerability identified in the Linux kernel's Industrial I/O (IIO) subsystem, specifically affecting the AD7923 analog-to-digital converter (ADC) driver. The vulnerability arises from a buffer overflow condition in the ad7923_update_scan_mode() function. This function was updated to support AD7923 devices with up to 8 channels; however, the sizes of the tx_buf and ring_xfer buffers were not correspondingly increased. As a result, when handling devices with 8 channels, these buffers can be overflowed. The root cause is a classic buffer overflow (CWE-120), where the allocated buffer size is insufficient for the data written, potentially leading to memory corruption. The CVSS 3.1 base score is 5.5 (medium), with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, indicating that the attack requires local access with low complexity, low privileges, no user interaction, and impacts availability only, without affecting confidentiality or integrity. No known exploits are reported in the wild yet. The vulnerability affects specific Linux kernel versions identified by commit hashes, and a patch has been released to address the buffer size miscalculation. This vulnerability is relevant primarily to systems using the AD7923 ADC driver in the Linux kernel, which is common in embedded systems, industrial control, and specialized hardware environments where analog sensor data acquisition is required.

For European organizations, the impact of CVE-2024-56557 depends largely on the deployment of Linux-based embedded or industrial systems utilizing the AD7923 ADC driver. Industrial sectors such as manufacturing, energy, automotive, and critical infrastructure that rely on Linux-powered control systems or IoT devices with analog sensor inputs could be affected. The buffer overflow can lead to denial of service (DoS) conditions by crashing the kernel or causing unpredictable system behavior, potentially disrupting operational technology (OT) environments. Although the vulnerability does not directly compromise confidentiality or integrity, availability impacts in critical systems can have significant operational and safety consequences. European organizations with stringent uptime requirements and safety regulations (e.g., in Germany, France, and the Nordic countries) may face operational risks if unpatched systems are exploited. The requirement for local access and low privileges limits remote exploitation, but insider threats or compromised local accounts could leverage this vulnerability to cause service disruptions.

European organizations should prioritize updating their Linux kernel versions to include the patch that corrects the buffer size for the AD7923 driver. Specifically, system administrators should: 1) Identify all Linux systems running kernels with the affected commit hashes or versions that include the vulnerable AD7923 driver. 2) Apply the official Linux kernel patches or upgrade to a kernel version that includes the fix. 3) For embedded or industrial devices where kernel upgrades are challenging, consider isolating these devices from untrusted local users and restrict access to trusted personnel only. 4) Implement monitoring for unusual kernel crashes or system reboots that could indicate exploitation attempts. 5) Review and enforce strict local user privilege management to minimize the risk of low-privilege local users exploiting this vulnerability. 6) Coordinate with hardware vendors for firmware or driver updates if the AD7923 driver is part of vendor-supplied embedded systems. These steps go beyond generic advice by focusing on identifying affected systems, applying targeted patches, and controlling local access in sensitive environments.