CVE-2025-59699 is a vulnerability in Entrust nShield hardware security modules (HSMs), specifically the Connect XC, 5c, and HSMi models running firmware versions through 13.6.11 or 13.7. The root cause is insecure default configurations in the Legacy GRUB Bootloader, which allows booting from external USB devices without sufficient security controls. An attacker with physical proximity can exploit this by inserting a USB device containing a valid root filesystem and rebooting the HSM. This process bypasses normal authentication and security mechanisms, enabling privilege escalation to root level on the device. Given that HSMs are designed to securely store cryptographic keys and perform sensitive cryptographic operations, such unauthorized access can compromise the confidentiality and integrity of cryptographic material and disrupt availability. The vulnerability is rated with a CVSS 3.1 score of 6.8 (medium severity), reflecting the requirement for physical access but the high impact on confidentiality, integrity, and availability. No patches or exploits are currently documented, but the risk remains significant due to the critical role of HSMs in secure environments. The vulnerability is categorized under CWE-290 (Authentication Bypass by Spoofing), emphasizing the bypass of bootloader security controls. Organizations relying on these Entrust HSMs should review bootloader configurations and physical security policies to mitigate risk.

The impact of CVE-2025-59699 on European organizations is substantial due to the critical role of Entrust nShield HSMs in securing cryptographic keys used for data protection, authentication, and digital signatures. Successful exploitation can lead to full compromise of the HSM, exposing sensitive cryptographic keys and enabling attackers to decrypt confidential data, forge digital signatures, or disrupt cryptographic services. This can undermine trust in secure communications, financial transactions, and identity management systems. Industries such as banking, government agencies, telecommunications, and critical infrastructure operators in Europe are particularly at risk. The requirement for physical access limits remote exploitation but increases the threat from insider attackers or attackers with physical access during maintenance or in less secure environments. The vulnerability could also facilitate supply chain attacks or targeted espionage. Disruption or compromise of HSMs could lead to regulatory non-compliance, financial losses, and reputational damage.

To mitigate CVE-2025-59699, organizations should implement the following specific measures: 1) Disable Legacy GRUB Bootloader support or configure it to disallow booting from external USB devices unless explicitly authorized. 2) Enable secure boot mechanisms where supported to ensure only trusted firmware and bootloaders are executed. 3) Physically secure HSM devices in locked, access-controlled environments with surveillance and logging to prevent unauthorized physical access. 4) Regularly audit and verify bootloader configurations and firmware versions to detect insecure defaults or unauthorized changes. 5) Implement strict operational procedures for maintenance personnel, including supervision and access logging. 6) Coordinate with Entrust for firmware updates or patches addressing this vulnerability once available. 7) Consider network segmentation and monitoring to detect anomalous activity that could indicate compromise of HSMs. 8) Conduct security awareness training for staff on the risks of physical attacks and insider threats related to HSMs.