CVE-2024-57256 is an integer overflow vulnerability classified under CWE-190 found in the ext4fs_read_symlink function of the denx U-Boot bootloader prior to version 2025.01-rc1. The vulnerability occurs when the function processes a crafted ext4 filesystem containing an inode size field set to 0xffffffff (maximum 32-bit unsigned integer). During the processing, the code attempts to allocate memory by adding one to this inode size value, which causes an integer overflow due to the 32-bit limit, resulting in a zero-sized allocation via malloc. This zero allocation leads to a memory overwrite when the code subsequently writes data, potentially corrupting adjacent memory regions. The flaw impacts confidentiality, integrity, and availability of the system because it can lead to arbitrary code execution or system crashes during the boot process. Exploitation requires an attacker to supply a malicious ext4 filesystem image to the bootloader, which is typically accessed during device startup. The CVSS v3.1 base score is 7.1, reflecting high severity with attack vector being physical or local (AV:P), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), and a scope change (S:C) affecting confidentiality, integrity, and availability (C:H/I:H/A:H). No public exploits are known at this time, but the vulnerability poses a significant risk to embedded devices using affected U-Boot versions. The vulnerability is particularly relevant for embedded and IoT devices that rely on U-Boot for bootstrapping and filesystem mounting.

The impact of CVE-2024-57256 on European organizations is significant, especially those operating embedded systems, industrial control systems, IoT devices, or network equipment that utilize U-Boot as their bootloader. Successful exploitation can lead to arbitrary code execution or denial of service at the bootloader stage, potentially allowing attackers to compromise device firmware integrity, gain persistent control, or disrupt device availability. This can affect critical infrastructure, manufacturing equipment, telecommunications hardware, and other embedded devices prevalent in European industries. The confidentiality of sensitive data stored or processed on these devices may also be at risk due to memory corruption. Given the widespread use of U-Boot in embedded devices across Europe, the vulnerability could have cascading effects on supply chains and operational technology environments. The requirement for physical or local access to the device limits remote exploitation but does not eliminate risk in environments where devices are accessible to insiders or attackers with physical proximity. The lack of known exploits currently provides a window for proactive mitigation.

To mitigate CVE-2024-57256, European organizations should: 1) Monitor for and apply updates to U-Boot bootloader versions as soon as patches become available from denx or device vendors. 2) Implement strict validation and integrity checks on ext4 filesystem images before they are loaded by the bootloader to detect and reject malformed or suspicious filesystems. 3) Restrict physical and local access to devices running vulnerable U-Boot versions to prevent attackers from supplying crafted filesystem images. 4) Employ secure boot mechanisms where possible to ensure only trusted bootloaders and filesystem images are executed. 5) Use hardware security modules or trusted platform modules (TPMs) to protect boot integrity. 6) Conduct regular firmware audits and penetration testing focusing on bootloader and filesystem handling. 7) Segment networks and isolate critical embedded devices to limit attack surface. 8) Monitor device logs and behavior for anomalies during boot that may indicate exploitation attempts. These steps go beyond generic advice by focusing on bootloader-specific controls, filesystem validation, and physical security.