CVE-2025-0622 is a use-after-free vulnerability identified in the GRUB2 bootloader, specifically within the command/gpg component. The issue arises because hooks created by dynamically loaded modules are not properly removed when their corresponding modules are unloaded. This leads to a scenario where GRUB2 may invoke hooks that reference memory that has already been freed, causing a use-after-free condition. An attacker with high privileges on the system can exploit this flaw by unloading a module and then forcing GRUB2 to call the stale hooks, resulting in arbitrary code execution during the boot process. This is particularly critical as it can allow bypassing secure boot protections, undermining the system's trusted boot chain and potentially enabling persistent, low-level compromise. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector limited to local access, requiring high privileges, no user interaction, and impacting confidentiality, integrity, and availability. Although no public exploits are known at this time, the technical nature of the flaw and its impact on secure boot mechanisms make it a significant concern for environments relying on GRUB2 for secure system startup.

For European organizations, the impact of CVE-2025-0622 can be substantial, especially in sectors that rely heavily on secure boot mechanisms to ensure system integrity, such as government, finance, healthcare, and critical infrastructure. Successful exploitation could allow attackers to execute arbitrary code at boot time, bypassing secure boot protections and potentially implanting persistent malware that is difficult to detect or remove. This compromises the confidentiality and integrity of sensitive data and disrupts availability by destabilizing or controlling system startup. Organizations using GRUB2 on Linux servers, embedded systems, or workstations with secure boot enabled are at risk. The requirement for high privileges limits the attack surface to insiders or attackers who have already gained elevated access, but the severity of the impact justifies urgent mitigation. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as proof-of-concept exploits could emerge.

To mitigate CVE-2025-0622, European organizations should: 1) Monitor for and apply vendor patches or updates to GRUB2 as soon as they become available, ensuring the removal of the use-after-free condition. 2) Restrict administrative and root-level access to systems using GRUB2, minimizing the risk of local privilege abuse. 3) Implement strict access controls and auditing on systems that support secure boot to detect unauthorized module loading/unloading activities. 4) Employ system integrity monitoring tools to detect anomalous behavior during the boot process. 5) Consider using hardware-based secure boot enforcement and trusted platform modules (TPM) to strengthen boot chain security. 6) Educate system administrators about the risks of unloading modules and the importance of secure boot configurations. 7) For critical infrastructure, establish incident response plans that include boot-level compromise scenarios. These steps go beyond generic advice by focusing on access control, monitoring, and boot process integrity specific to this vulnerability.