CVE-2025-0622 is a use-after-free vulnerability identified in the GRUB2 bootloader, specifically related to the handling of hooks created by dynamically loaded modules. When a module that registered hooks is unloaded, the hooks are not properly removed, causing GRUB2 to call these dangling hooks. This results in a use-after-free condition, which can be exploited by an attacker to execute arbitrary code within the bootloader context. The vulnerability requires the attacker to have high privileges and local access to the system, as well as the ability to unload modules and trigger the hook invocation. Exploitation could allow bypassing secure boot protections, undermining the trusted boot process and potentially enabling persistent, low-level compromise of the system. The CVSS 3.1 base score is 6.4, with vector AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local attack vector, high attack complexity, high privileges required, no user interaction, unchanged scope, and high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild. The vulnerability affects GRUB2 versions where this module hook unloading flaw exists, though specific affected versions are not detailed. The flaw was reserved in January 2025 and published in February 2025. The issue was assigned by Red Hat and enriched by CISA, indicating recognition by major security entities. This vulnerability is critical for environments relying on secure boot and GRUB2 for system integrity and trusted boot processes.

For European organizations, the impact of CVE-2025-0622 can be significant, particularly for those using Linux-based systems with GRUB2 as the bootloader and secure boot enabled. Successful exploitation can lead to arbitrary code execution at the bootloader level, allowing attackers to bypass secure boot protections and compromise the system before the operating system loads. This undermines the root of trust and can facilitate persistent malware infections, data theft, or system sabotage. Critical infrastructure sectors such as finance, energy, healthcare, and government agencies that rely on secure boot for system integrity are at heightened risk. The requirement for high privileges and local access limits remote exploitation but does not eliminate insider threats or attacks leveraging other vulnerabilities to gain local access. The vulnerability affects confidentiality, integrity, and availability, potentially leading to data breaches, operational disruptions, and loss of trust in system security. Given the widespread use of GRUB2 in Linux distributions across Europe, many organizations could be exposed if patches are not applied promptly.

1. Apply official patches from GRUB2 maintainers or Linux distribution vendors as soon as they become available to address the use-after-free flaw. 2. Until patches are deployed, restrict local administrative access to trusted personnel only and monitor for suspicious module unloading activities. 3. Implement strict access controls and auditing on systems to detect unauthorized attempts to unload modules or manipulate bootloader configurations. 4. Use secure boot configurations that include additional integrity checks and tamper detection mechanisms to reduce the risk of bootloader compromise. 5. Employ endpoint detection and response (EDR) tools capable of monitoring boot processes and detecting anomalous behavior related to bootloader hooks. 6. Conduct regular security training for system administrators on the risks of local privilege misuse and the importance of patch management. 7. Consider deploying hardware-based root of trust solutions (e.g., TPM) to complement secure boot and mitigate bootloader-level attacks. 8. Maintain up-to-date inventories of systems running GRUB2 and prioritize patching on critical infrastructure and high-value assets.