CVE-2024-45776 is a vulnerability in the GRUB2 bootloader, specifically in the grub_mofile_open() function responsible for reading language .mo files. The issue stems from a failure to properly verify an integer overflow during the allocation of an internal buffer. When a crafted .mo file is processed, the buffer size calculation can overflow, causing the program to allocate insufficient memory and subsequently perform out-of-bounds reads and writes. This memory corruption can lead to leakage of sensitive information or overwriting of critical data structures within the bootloader environment. Such corruption may allow an attacker to circumvent secure boot protections, potentially enabling unauthorized code execution or persistence at a very early stage of system startup. The vulnerability requires local access with high privileges (PR:H) and does not require user interaction (UI:N). The attack vector is local (AV:L), meaning remote exploitation is not feasible without prior access. The CVSS v3.1 base score is 6.7, reflecting medium severity due to the combination of high impact on confidentiality, integrity, and availability, but limited by the requirement for privileged local access. No known exploits have been reported in the wild as of the publication date. The vulnerability affects all versions of GRUB2 that handle language .mo files in the described manner, which is common in many Linux distributions and embedded systems using GRUB2 as the bootloader.

For European organizations, this vulnerability poses a significant risk primarily to systems using GRUB2 as their bootloader, which includes a vast majority of Linux-based servers and workstations. The ability to leak sensitive data or overwrite critical bootloader data can compromise system integrity and confidentiality, potentially allowing attackers to bypass secure boot mechanisms designed to prevent unauthorized code execution during system startup. This could lead to persistent malware infections, unauthorized access to sensitive environments, and disruption of critical services. Sectors such as finance, healthcare, government, and critical infrastructure in Europe, which rely heavily on Linux servers, are particularly vulnerable. The requirement for local privileged access limits the attack surface but does not eliminate risk, especially in environments where insider threats or lateral movement by attackers are concerns. The absence of known exploits currently provides a window for proactive mitigation, but the potential for future exploitation necessitates urgent attention.

1. Apply patches from Linux distribution vendors or GRUB2 maintainers as soon as they become available to address the integer overflow and buffer allocation issue. 2. Restrict local access to systems running GRUB2 to trusted administrators only, minimizing the risk of exploitation by unauthorized users. 3. Implement strict access controls and monitoring on systems with GRUB2 to detect any unauthorized attempts to modify or replace language .mo files or bootloader components. 4. Employ secure boot and measured boot technologies alongside GRUB2 to enhance boot integrity verification and detect tampering. 5. Regularly audit and harden bootloader configurations and file permissions to prevent unauthorized file manipulations. 6. Use endpoint detection and response (EDR) solutions capable of monitoring low-level system changes that could indicate exploitation attempts. 7. Educate system administrators about the risks of local privilege escalation and the importance of maintaining secure boot environments.