CVE-2024-38575 is a vulnerability identified in the Linux kernel's brcmfmac wireless driver, specifically related to the PCIe interface handling in the Broadcom FullMAC wireless chipset driver. The issue arises in the function brcmf_pcie_download_fw_nvram(), where the kernel attempts to allocate memory using kzalloc() for a buffer named randbuf. If the system's physical memory is exhausted, kzalloc() returns a NULL pointer. Subsequently, the code calls get_random_bytes() to fill this randbuf with random data without verifying the allocation's success. This leads to a NULL pointer dereference, causing a kernel crash or denial of service (DoS) due to kernel panic. The vulnerability stems from improper error handling of memory allocation failure and unsafe use of the random byte generation function on a NULL pointer. To mitigate this, the Linux kernel patch introduces a separate function that uses a buffer allocated on the kernel stack rather than heap memory to generate random bytes for randbuf. This approach prevents allocation failure and avoids potential kernel stack overflow, thereby eliminating the NULL pointer dereference condition. The vulnerability affects multiple versions of the Linux kernel as indicated by the commit hashes listed, and it was publicly disclosed on June 19, 2024. There are no known exploits in the wild at this time, and no CVSS score has been assigned yet. However, the flaw primarily results in a denial of service condition rather than privilege escalation or arbitrary code execution.

For European organizations, this vulnerability could lead to system instability or downtime on Linux-based systems utilizing the affected Broadcom wireless drivers, particularly in environments with constrained physical memory or heavy wireless usage. The denial of service caused by kernel crashes could disrupt critical services, especially in sectors relying on wireless connectivity such as telecommunications, manufacturing with IoT devices, and enterprise networks. Systems running embedded Linux or network appliances with Broadcom FullMAC chipsets are at risk. Although the vulnerability does not appear to allow remote code execution or privilege escalation, the resulting kernel panic could be exploited by attackers to cause repeated crashes, impacting availability and potentially leading to operational disruptions. This is particularly relevant for European organizations with strict uptime requirements and regulatory obligations for service continuity. Additionally, the vulnerability might affect cloud providers and data centers in Europe running Linux servers with affected drivers, potentially impacting hosted services and customer workloads.

European organizations should promptly apply the official Linux kernel patches that address this vulnerability by implementing the updated function that safely handles random byte generation without risking NULL pointer dereference. System administrators should verify that their Linux distributions have incorporated these fixes and update kernel versions accordingly. For environments where immediate patching is not feasible, temporary mitigations include monitoring system logs for kernel oops or panic events related to brcmfmac and limiting workloads that heavily utilize wireless interfaces to reduce memory pressure. Additionally, organizations should audit their hardware inventory to identify devices using Broadcom FullMAC chipsets with PCIe interfaces and prioritize patching those systems. Implementing robust memory monitoring and alerting can help detect conditions that might trigger this vulnerability. Finally, maintaining strong incident response procedures to quickly recover from potential denial of service events will minimize operational impact.