CVE-2025-59697 is a vulnerability in Entrust nShield hardware security modules (HSMs), specifically the Connect XC, 5c, and HSMi models up to firmware versions 13.6.11 and 13.7. The flaw allows a physically proximate attacker who already has high privileges on the host system to modify the Legacy GRUB bootloader configuration. By editing this configuration, the attacker can configure the system to spawn a root shell upon the next boot, effectively escalating their privileges to full root access. This attack vector leverages weaknesses in bootloader security controls and insufficient protection of boot configuration files. The vulnerability is categorized under CWE-284 (Improper Access Control) and CWE-269 (Improper Privilege Management), highlighting failures in enforcing correct privilege boundaries. The CVSS v3.1 score is 7.2, indicating high severity, with an attack vector of physical proximity (AV:P), low attack complexity (AC:L), requiring high privileges (PR:H), no user interaction (UI:N), and a scope change (S:C) that affects confidentiality, integrity, and availability (C:H/I:H/A:H). Although no exploits are currently known in the wild, the potential impact is severe given the critical role of HSMs in securing cryptographic keys and sensitive operations. The vulnerability underscores the importance of securing physical access and bootloader configurations in environments that deploy these HSMs.

For European organizations, the impact of CVE-2025-59697 is significant due to the critical role Entrust nShield HSMs play in securing cryptographic keys, digital signatures, and sensitive transactions. Successful exploitation could lead to full root access on the host OS, enabling attackers to extract cryptographic material, manipulate secure operations, or disrupt availability. This compromises confidentiality, integrity, and availability of protected assets, potentially undermining trust in digital services, financial transactions, and government operations. Sectors such as banking, telecommunications, government agencies, and critical infrastructure operators are particularly at risk. The requirement for physical proximity and existing high privileges limits the attack surface but does not eliminate risk, especially in environments with shared or insufficiently secured physical access. The vulnerability could facilitate insider threats or targeted attacks by adversaries with limited but physical access to systems running vulnerable HSMs.

1. Restrict physical access to servers hosting Entrust nShield HSMs by enforcing strict access controls, surveillance, and secure facilities. 2. Harden bootloader configurations by implementing secure boot mechanisms and protecting GRUB configuration files with appropriate permissions and integrity checks. 3. Monitor and audit changes to bootloader configurations and system firmware to detect unauthorized modifications promptly. 4. Apply vendor patches or firmware updates as soon as they become available to address this vulnerability. 5. Employ hardware security features such as TPM or UEFI Secure Boot where supported to prevent unauthorized bootloader tampering. 6. Conduct regular security training for administrators to recognize and prevent privilege escalation attempts. 7. Implement multi-factor authentication and role-based access controls to minimize the risk of privilege misuse. 8. Consider network segmentation and isolation of critical HSM hosts to reduce exposure. 9. Develop incident response plans that include scenarios involving physical tampering and privilege escalation.