CVE-2024-46684 is a vulnerability identified in the Linux kernel specifically related to the binfmt_elf_fdpic subsystem, which handles the loading of ELF binaries with FDPIC (Function Descriptor PIC) support. The issue arises in the function create_elf_fdpic_tables(), which is responsible for setting up the auxiliary vector (AUXV) entries that provide runtime information to ELF binaries. When the architecture defines ELF_HWCAP2, the calculation of the AUXV size was incorrect. Prior to the fix introduced by commit 10e29251be0e, this miscalculation led to the last AUX vector entry being set to zero, which was benign but incorrect. However, after the commit, the same miscalculation causes a kernel BUG, effectively a kernel panic or crash. The root cause is that the function did not account for the additional AUXV entry required when ELF_HWCAP2 is defined, leading to an off-by-one error in the number of AUXV entries allocated. The fix involves incrementing the number of AUXV entries by one in this scenario to prevent the kernel from crashing. This vulnerability affects Linux kernel versions that include the faulty commit and impacts architectures that define ELF_HWCAP2, which typically relates to certain ARM or other embedded architectures supporting extended hardware capabilities. No known exploits are reported in the wild at this time, and no CVSS score has been assigned yet. The vulnerability can cause denial of service through kernel crashes when affected binaries are loaded, potentially impacting system stability and availability.

For European organizations, the primary impact of CVE-2024-46684 is the risk of denial of service due to kernel crashes on affected Linux systems. This can disrupt critical services, especially in environments running embedded or ARM-based Linux systems where ELF_HWCAP2 is defined. Industries relying on Linux for infrastructure, IoT devices, telecommunications, or embedded systems could experience outages or degraded performance. The vulnerability does not appear to allow privilege escalation or data compromise directly but can affect system availability and reliability. Organizations with Linux-based servers, network equipment, or industrial control systems using affected kernel versions may face operational interruptions. The lack of known exploits reduces immediate risk, but the kernel BUG triggered by this flaw could be leveraged in targeted attacks to cause service disruption. European entities with high dependence on Linux infrastructure, particularly in sectors like finance, healthcare, manufacturing, and critical infrastructure, should be vigilant. The impact is more pronounced in environments where uptime and system stability are critical, and where affected architectures are in use.

To mitigate CVE-2024-46684, European organizations should: 1) Identify Linux systems running kernel versions containing the faulty commit (10e29251be0e) and determine if they operate on architectures defining ELF_HWCAP2, such as certain ARM platforms. 2) Apply the official Linux kernel patches that fix the AUXV size calculation as soon as they become available from trusted Linux distributions or kernel maintainers. 3) For embedded or specialized devices, coordinate with vendors to obtain updated firmware or kernel versions incorporating the fix. 4) Implement robust monitoring to detect kernel panics or crashes that could indicate exploitation or triggering of this vulnerability. 5) Consider deploying kernel live patching solutions where feasible to minimize downtime during patch application. 6) Maintain strict change management and testing procedures to ensure stability post-patching. 7) Limit exposure by restricting access to vulnerable systems and minimizing the execution of untrusted ELF binaries that could trigger the flaw. These steps go beyond generic advice by focusing on architecture-specific identification, vendor coordination, and operational monitoring tailored to this vulnerability's characteristics.