CVE-2024-56634 is a vulnerability identified in the Linux kernel specifically within the GPIO (General Purpose Input/Output) subsystem's grgpio driver. The issue arises because the function devm_kasprintf(), which is used in the grgpio_probe function, can return a NULL pointer upon failure. However, the original grgpio_probe implementation did not check for this NULL return value. This lack of validation can lead to a kernel NULL pointer dereference error, which typically results in a kernel panic or system crash. The vulnerability is rooted in improper error handling and pointer validation in kernel code, which is critical given the kernel's privileged execution context. Exploiting this flaw could allow a local attacker or a malicious process with the ability to trigger the grgpio_probe function to cause a denial of service (DoS) by crashing the system. There is no indication that this vulnerability allows privilege escalation or arbitrary code execution. The vulnerability has been addressed by adding a NULL pointer check in the grgpio_probe function to properly handle the failure case of devm_kasprintf(). The affected versions are identified by specific commit hashes, indicating that this issue is present in certain recent Linux kernel builds prior to the patch. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the primary impact of CVE-2024-56634 is the risk of denial of service on Linux systems that utilize the affected GPIO driver. This could affect embedded systems, IoT devices, industrial control systems, or servers running custom Linux kernels that include the grgpio driver. Organizations relying on such systems for critical infrastructure or operational technology could experience service interruptions, potentially impacting business continuity or safety-critical operations. Since the vulnerability requires triggering the grgpio_probe function, exploitation may require local access or specific conditions, limiting remote exploitation risk. However, in environments where untrusted users or processes have access to the system, this vulnerability could be leveraged to cause system instability. The impact on confidentiality and integrity is minimal as the vulnerability does not appear to allow code execution or privilege escalation. Nonetheless, availability disruption could have cascading effects, especially in sectors like manufacturing, energy, or transportation prevalent in Europe.

European organizations should promptly apply the patch that adds the NULL pointer check in the grgpio_probe function as soon as it is available in their Linux kernel distributions. For environments using custom or embedded Linux kernels, developers should review their kernel source to ensure this fix is incorporated. Additionally, organizations should audit systems to identify those running affected kernel versions with the grgpio driver enabled. Limiting local access to trusted users and processes can reduce the risk of exploitation. Implementing kernel hardening techniques such as kernel lockdown, SELinux/AppArmor policies, and restricting module loading can further mitigate potential attack vectors. Monitoring system logs for kernel panics or crashes related to GPIO operations can help detect attempted exploitation. Finally, organizations should maintain an inventory of embedded and IoT devices running Linux kernels to ensure timely updates and patch management.