CVE-2025-61664 is a Use After Free vulnerability identified in the GNU GRUB2 bootloader, specifically within its normal module. The flaw occurs because the normal_exit command is not properly unregistered when its associated module is unloaded. This improper cleanup leads to a dangling pointer scenario where the system may invoke the normal_exit command after the module has been removed, causing the bootloader to access memory that has already been freed. This memory corruption can result in a system crash (denial of service) or potentially allow an attacker to manipulate memory contents, impacting data confidentiality and integrity. The vulnerability requires local access to the system, has a high attack complexity, and does not require privileges or user interaction, which limits its exploitability. GRUB2 is widely used as the default bootloader in many Linux distributions, making this vulnerability relevant to a broad range of systems. Although no public exploits are known at this time, the flaw poses a risk especially in environments where local access is possible, such as multi-user systems or shared hosting environments. The CVSS v3.1 base score of 4.9 reflects the medium severity, considering the local attack vector and high complexity. The vulnerability was published on November 18, 2025, and no patches or exploits are currently listed, indicating that mitigation efforts should focus on vendor updates and access controls.

For European organizations, the impact of CVE-2025-61664 can be significant in environments relying heavily on Linux systems using GRUB2 as the bootloader. The vulnerability could lead to system instability or crashes, causing downtime for critical services. In worst cases, it may allow attackers to compromise data confidentiality and integrity by exploiting memory corruption, potentially leading to unauthorized data access or modification. Sectors such as finance, healthcare, government, and critical infrastructure, which often use Linux servers, could face operational disruptions and data breaches. The local access requirement limits remote exploitation, but insider threats or attackers with physical or remote local access could leverage this vulnerability. Additionally, systems that do not have strict access controls or are shared among multiple users are at higher risk. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time. The medium severity score suggests that while the vulnerability is not critical, it should not be ignored due to the potential for denial of service and data compromise.

1. Monitor vendor communications closely and apply official patches or updates for GRUB2 as soon as they become available. 2. Restrict local access to systems running GRUB2, ensuring only trusted users have physical or local login capabilities. 3. Implement strict user privilege separation and limit the ability to execute bootloader commands to authorized personnel only. 4. Employ system integrity monitoring to detect abnormal behavior or crashes related to the bootloader. 5. Use secure boot mechanisms and firmware protections to prevent unauthorized modification of bootloader components. 6. In multi-tenant or shared environments, isolate user sessions and restrict access to bootloader interfaces. 7. Conduct regular security audits focusing on bootloader configurations and access controls. 8. Educate system administrators about the vulnerability and the importance of timely patching and access restrictions. 9. Consider deploying intrusion detection systems that can alert on suspicious local activity related to bootloader commands. 10. Maintain up-to-date backups to enable recovery in case of system crashes or data integrity issues caused by exploitation.