CVE-2024-47756 is a vulnerability identified in the Linux kernel, specifically within the PCI subsystem's keystone driver code. The issue arises from a logical error in the conditional statement of the function ks_pcie_quirk(). The original code mistakenly used a logical AND (&&) operator where a logical OR (||) was intended. This incorrect condition can lead to a NULL pointer dereference, which occurs when the program attempts to access or manipulate memory through a pointer that is null (i.e., points to no valid memory). Such a dereference typically results in a kernel panic or system crash, causing a denial of service (DoS) condition. The vulnerability affects multiple versions of the Linux kernel, as indicated by the various commit hashes listed, and was publicly disclosed on October 21, 2024. The fix involves correcting the if-statement to use the proper logical operator, thereby preventing the NULL dereference. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet. The vulnerability does not appear to allow privilege escalation or arbitrary code execution but can disrupt system availability due to crashes triggered by the NULL dereference.

For European organizations, the primary impact of CVE-2024-47756 is the potential for denial of service on systems running affected Linux kernel versions with the keystone PCI driver. This can lead to unexpected system crashes, service interruptions, and potential downtime for critical infrastructure, especially in environments relying on Linux-based servers, embedded systems, or network devices using the keystone PCI hardware. Industries such as telecommunications, manufacturing, and cloud service providers that depend heavily on Linux servers could experience operational disruptions. While the vulnerability does not directly compromise confidentiality or integrity, the availability impact can affect business continuity and service level agreements. Additionally, systems that are part of critical infrastructure or real-time control systems may face safety or operational risks if the kernel crashes unexpectedly. Since no authentication or user interaction is required to trigger the NULL dereference, remote or local attackers with the ability to influence the PCI device state or driver behavior could potentially exploit this flaw to cause system instability.

European organizations should prioritize updating their Linux kernel to the patched version that corrects the logical operator in the ks_pcie_quirk() function. Kernel updates should be tested in staging environments to ensure compatibility and stability before deployment in production. Organizations should audit their systems to identify those running affected kernel versions and verify if the keystone PCI driver is in use, as the vulnerability is specific to this driver. For systems where immediate patching is not feasible, consider isolating affected devices or disabling the keystone PCI driver if it is not critical to operations. Monitoring system logs for kernel panics or crashes related to PCI device interactions can help detect exploitation attempts. Additionally, implementing robust system recovery procedures and maintaining up-to-date backups will reduce downtime in case of crashes. Network segmentation and strict access controls can limit attacker ability to trigger the vulnerability remotely. Finally, stay informed about any emerging exploit reports or additional patches from the Linux kernel maintainers.