CVE-2025-0622 is a use-after-free vulnerability identified in the GRUB2 bootloader, specifically related to the handling of hooks created by loaded modules. In certain scenarios, when a module is unloaded, the hooks it registered are not properly removed. This flaw allows an attacker to trigger GRUB2 to invoke these stale hooks after their associated module has been unloaded, resulting in a use-after-free condition. Exploiting this vulnerability could enable an attacker to execute arbitrary code within the GRUB2 context. Since GRUB2 operates at a very early stage in the boot process and is responsible for loading the operating system, successful exploitation can lead to bypassing secure boot protections, which are designed to ensure that only trusted software is loaded during system startup. The vulnerability has a CVSS 3.1 base score of 6.4, indicating a medium severity level. The vector details highlight that exploitation requires local access (AV:L), high attack complexity (AC:H), and high privileges (PR:H), with no user interaction (UI:N). The impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). No known exploits are currently reported in the wild, and no patches or vendor-specific details are provided in the available information. This vulnerability is significant because it targets the bootloader, a critical component in system security, and successful exploitation could undermine foundational security mechanisms such as secure boot, potentially allowing persistent and stealthy compromise of affected systems.

For European organizations, the impact of CVE-2025-0622 could be substantial, particularly for those relying on GRUB2 as their bootloader in Linux-based environments. The ability to bypass secure boot protections threatens the integrity of the entire system startup process, potentially allowing attackers to install persistent rootkits or other malware that operate below the operating system level. This could lead to long-term undetected compromises, data breaches, and disruption of critical services. Organizations in sectors such as finance, healthcare, government, and critical infrastructure, which often enforce strict secure boot policies to protect sensitive data and maintain regulatory compliance, are at heightened risk. Additionally, the requirement for local high-privilege access means that insider threats or attackers who have already gained elevated access could leverage this vulnerability to deepen their control over systems. The medium CVSS score reflects the complexity and prerequisites for exploitation, but the potential consequences justify proactive mitigation, especially in environments where secure boot is a key security control.

To mitigate CVE-2025-0622 effectively, organizations should: 1) Monitor for and apply vendor patches or updates to GRUB2 as soon as they become available, even though no patch links are currently provided; 2) Restrict and monitor local administrative access rigorously to prevent attackers from gaining the high privileges required to exploit this vulnerability; 3) Implement strong physical security controls to limit unauthorized local access to critical systems; 4) Employ integrity monitoring tools that can detect unauthorized changes to bootloader configurations or binaries; 5) Consider deploying additional boot-time security mechanisms such as measured boot and hardware-based root of trust technologies (e.g., TPM) to complement secure boot and detect anomalies; 6) Conduct regular audits of secure boot configurations and ensure that secure boot policies are enforced and not disabled; 7) Educate system administrators about the risks of unloading modules and the importance of secure boot integrity; 8) In environments where GRUB2 is used, consider isolating critical systems or using alternative bootloaders with a stronger security track record if immediate patching is not feasible.