CVE-2024-42117 is a vulnerability identified in the Linux kernel specifically within the Direct Rendering Manager (DRM) subsystem for AMD display drivers. The issue arises from improper handling of index values returned by two internal functions: find_disp_cfg_idx_by_plane_id and find_disp_cfg_idx_by_stream_id. These functions are designed to return an array index corresponding to a plane or stream ID. However, when the requested ID is not found, they return -1, which is not a valid array index. The Linux kernel code currently uses ASSERT() to catch these invalid cases and attempts to return a positive number less than the array size to avoid out-of-bounds access. This vulnerability was discovered through static analysis tools like Coverity, which reported four overrun and two negative return issues. The root cause is the potential for out-of-bounds array access or negative index usage, which could lead to undefined behavior, including memory corruption or kernel crashes. The patch involves modifying the functions to avoid returning invalid indices and ensuring that callers receive valid, bounded indices, preventing overruns and negative returns. Although no known exploits are reported in the wild, the vulnerability affects the Linux kernel versions identified by the commit hash 7966f319c66d9468623c6a6a017ecbc0dd79be75, indicating a recent code revision. The flaw is technical and low-level, impacting the graphics subsystem's stability and security, particularly on systems using AMD GPUs with the affected DRM driver code.

For European organizations, the impact of CVE-2024-42117 primarily concerns systems running Linux kernels with AMD GPU drivers, especially in environments where graphics processing is critical, such as data centers, cloud providers, research institutions, and enterprises relying on Linux-based workstations or servers. Exploitation could lead to kernel crashes (denial of service) or potentially memory corruption, which might be leveraged for privilege escalation or arbitrary code execution by a local attacker. This risk is heightened in multi-tenant environments or shared systems where untrusted users have access. The vulnerability could disrupt business operations, cause system instability, or lead to data loss. Given the widespread use of Linux in European public sector, financial services, and industrial control systems, any instability or security breach could have cascading effects on critical infrastructure and services. However, the absence of known exploits and the requirement for local code execution or user interaction reduce the immediate threat level. Still, organizations with AMD GPU-enabled Linux systems should prioritize patching to maintain system integrity and availability.

European organizations should implement the following specific mitigation steps: 1) Identify all Linux systems utilizing AMD GPUs and verify the kernel version or commit hashes to determine if they include the vulnerable code. 2) Apply the latest Linux kernel updates or patches that address CVE-2024-42117 as soon as they become available from trusted sources or Linux distributions. 3) For environments where immediate patching is not feasible, consider disabling or limiting access to the affected DRM subsystem or AMD GPU drivers, especially for untrusted users or processes. 4) Employ kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR), SELinux/AppArmor policies, and restrict local user privileges to minimize exploitation potential. 5) Monitor system logs and kernel messages for unusual ASSERT() triggers or crashes related to the DRM subsystem, which might indicate attempted exploitation or instability. 6) Engage with Linux distribution security advisories and subscribe to relevant security mailing lists to stay informed about updates and exploit developments. 7) Conduct internal audits to ensure that systems exposed to untrusted users or running critical workloads are prioritized for patching.