CVE-2024-42118 is a vulnerability identified in the Linux kernel, specifically within the Direct Rendering Manager (DRM) subsystem for AMD graphics display handling. The issue arises from the function resource_stream_to_stream_idx, which is responsible for mapping a resource stream to an array index. When the function fails to find a valid stream, it returns -1, which is an invalid array index. This improper handling of the return value can lead to an out-of-bounds array access (overrun) and negative return value issues. Such behavior can cause memory corruption or undefined behavior in the kernel, potentially leading to system instability or crashes. The vulnerability was detected by static analysis tools like Coverity, which flagged the negative return value and overrun risks. The fix involves adding an assertion (ASSERT()) to catch the invalid condition and returning zero instead of -1 to prevent invalid array indexing. This correction eliminates the overrun and negative return issues by ensuring only valid indices are used. No known exploits are currently reported in the wild, and the vulnerability affects specific Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2. Since the vulnerability is in the kernel's graphics subsystem, it primarily affects systems using AMD GPUs with the vulnerable Linux kernel versions. The flaw could be exploited locally by an attacker with the ability to interact with the DRM subsystem, potentially leading to denial of service or privilege escalation through kernel memory corruption.

For European organizations, this vulnerability poses a risk primarily to servers, desktops, and embedded systems running vulnerable Linux kernel versions with AMD graphics hardware. The impact includes potential system crashes or instability due to kernel memory corruption, which can disrupt business operations, especially in environments relying on Linux for critical infrastructure or workstation use. While no active exploits are known, the vulnerability could be leveraged by local attackers or malicious software to escalate privileges or cause denial of service. This is particularly concerning for organizations with high security requirements, such as financial institutions, government agencies, and critical infrastructure operators. The vulnerability could also affect cloud service providers and data centers in Europe that use Linux-based AMD GPU-enabled servers for compute or graphical workloads, potentially impacting service availability and data integrity.

European organizations should prioritize updating their Linux kernels to versions that include the fix for CVE-2024-42118. Since the vulnerability is in the kernel DRM subsystem, applying official kernel patches or upgrading to the latest stable kernel releases from trusted Linux distributions is essential. Organizations should audit their systems to identify those running vulnerable kernel versions with AMD GPU hardware. For systems where immediate patching is not feasible, restricting access to the DRM subsystem and limiting local user privileges can reduce exploitation risk. Additionally, monitoring system logs for kernel warnings or crashes related to DRM or graphics drivers can help detect attempts to trigger the vulnerability. Employing kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR) and enabling security modules like SELinux or AppArmor can further mitigate exploitation impact. Finally, organizations should maintain robust incident response plans to quickly address any exploitation attempts.