CVE-2024-26964 is a vulnerability identified in the Linux kernel's USB xHCI (Extensible Host Controller Interface) driver, specifically within the function xhci_map_urb_for_dma(). This function is responsible for preparing USB Request Blocks (URBs) for Direct Memory Access (DMA) by creating a temporary linear buffer and copying scatter-gather (SG) lists into it. The vulnerability arises when the memory allocation function kzalloc_node() fails to allocate the required memory, returning a NULL pointer. The existing code does not properly handle this failure and proceeds to call sg_pcopy_to_buffer(), which attempts to copy data into the NULL pointer, leading to a kernel crash (NULL pointer dereference). This results in a denial of service (DoS) condition as the kernel becomes unstable or crashes. The fix involves adding error handling to detect kzalloc_node() failure and returning an -ENOMEM error code to prevent the unsafe memory copy operation. This vulnerability affects Linux kernel versions identified by the commit hash 2017a1e58472a27e532b9644b4a61dfe18f6baac and potentially other versions with similar code. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability is rooted in improper error handling and memory management in a critical USB subsystem of the Linux kernel, which is widely used across many distributions and devices.

For European organizations, the impact of CVE-2024-26964 primarily manifests as a potential denial of service on systems running vulnerable Linux kernels with USB xHCI support. This could disrupt operations on servers, workstations, or embedded devices that rely on USB connectivity, including peripherals such as storage devices, input devices, or specialized USB hardware. In environments where high availability is critical, such as financial institutions, healthcare providers, and industrial control systems, unexpected kernel crashes could lead to service outages, data loss, or operational downtime. Although this vulnerability does not appear to allow privilege escalation or remote code execution, the resulting instability could be exploited by attackers with local access to cause disruption. Given the widespread use of Linux in European data centers, cloud infrastructure, and IoT devices, the vulnerability could affect a broad range of sectors. However, the requirement for local access and the absence of known exploits reduce the immediate risk of large-scale attacks. Still, organizations with USB-dependent Linux systems should prioritize patching to maintain system stability and prevent potential denial of service scenarios.

To mitigate CVE-2024-26964, European organizations should: 1) Identify all Linux systems running kernels with the affected xHCI code, focusing on those using USB devices extensively. 2) Apply the official Linux kernel patches that add proper error handling in xhci_map_urb_for_dma(), ensuring that kzalloc_node() failures are correctly handled to prevent kernel crashes. 3) For systems where immediate patching is not feasible, consider disabling USB ports or restricting USB device usage to reduce exposure, especially on critical servers. 4) Implement monitoring for kernel crashes or unusual USB subsystem errors to detect potential exploitation attempts or instability. 5) Maintain strict local access controls and limit user permissions to reduce the risk of malicious local actors triggering the vulnerability. 6) Coordinate with hardware and Linux distribution vendors to receive timely updates and verify that patches are included in future kernel releases. 7) Conduct thorough testing of patches in staging environments to ensure stability before deployment in production. These steps go beyond generic advice by focusing on USB subsystem dependency, local access control, and proactive monitoring tailored to this specific vulnerability.