CVE-2024-36934 is a vulnerability identified in the Linux kernel's handling of user-space data copying within the bna (Broadcom NetXtreme II) driver code. The issue arises because the kernel allocates a buffer of size nbytes and copies nbytes from user space into this buffer without ensuring that the copied string is null-terminated. Subsequently, the kernel uses sscanf to parse this buffer. Since sscanf expects a null-terminated string, the absence of a terminating null character can cause an out-of-bounds (OOB) read when sscanf reads beyond the allocated buffer. This OOB read can lead to kernel memory disclosure or potentially cause kernel crashes due to invalid memory access. The fix involves replacing the memdup_user function with memdup_user_nul, which guarantees that the copied buffer is null-terminated, thereby preventing the OOB read condition. The vulnerability affects specific Linux kernel versions identified by commit hashes, indicating it is present in certain recent kernel builds prior to the patch. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability is technical in nature, involving kernel memory handling and string parsing functions, which are critical for kernel stability and security.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions with the affected bna driver, commonly found in environments using Broadcom NetXtreme II network adapters. The potential impact includes unauthorized disclosure of kernel memory contents due to OOB reads, which could leak sensitive information such as cryptographic keys or kernel data structures. Additionally, the vulnerability could be leveraged to cause denial of service (DoS) by crashing the kernel, impacting availability of critical systems. Organizations relying on Linux servers for infrastructure, cloud services, or network appliances could face operational disruptions. While exploitation requires local access or a vector to trigger the vulnerable code path, the severity is heightened in multi-tenant or shared environments where kernel memory disclosure could lead to privilege escalation or lateral movement. European sectors with high reliance on Linux-based infrastructure, such as finance, telecommunications, and government, could be particularly affected if patches are not applied promptly.

European organizations should prioritize updating their Linux kernels to versions that include the patch replacing memdup_user with memdup_user_nul in the bna driver. Specifically, kernel maintainers and system administrators should track official Linux kernel releases and apply security updates immediately. For environments where immediate patching is not feasible, organizations should audit the presence of Broadcom NetXtreme II network adapters and consider disabling or unloading the bna driver temporarily to mitigate risk. Additionally, implementing strict access controls to limit local user access can reduce the likelihood of exploitation. Monitoring kernel logs for unusual crashes or OOB read symptoms may help detect attempted exploitation. Organizations should also ensure that their vulnerability management processes include this CVE and verify that all Linux-based systems, including embedded devices and network appliances, are assessed and remediated accordingly.