CVE-2025-2486 is a vulnerability identified in the Ubuntu edk2 UEFI firmware packages, specifically versions 2024.05 and 2024.02. The issue arises from active debug code that inadvertently allowed the UEFI Shell to be accessed even when Secure Boot was enabled. Secure Boot is a security standard designed to ensure that only trusted firmware and software are executed during the boot process, preventing unauthorized code execution at a low level. The vulnerability is linked to CWE-489, which involves the presence of active debug code in production software, potentially exposing sensitive functionality. In this case, the debug code permitted the UEFI Shell to run, which could allow an attacker to bypass Secure Boot constraints by executing arbitrary commands or loading unsigned code during boot. Previous fixes for a related vulnerability (CVE-2023-48733) were incomplete, and this vulnerability represents an additional repair to fully enforce Secure Boot restrictions. The CVSS 4.0 score of 3.7 reflects a low severity, influenced by the requirement for local access, high attack complexity, and user interaction. No privileges or authentication are needed, but the attacker must have physical or local access to the system and interact with the boot process. Ubuntu addressed this vulnerability by disabling the UEFI Shell in the affected versions, thereby preventing unauthorized access to the Shell in Secure Boot environments. This fix restores the intended security posture of Secure Boot on Ubuntu systems using edk2 firmware packages.

The primary impact of CVE-2025-2486 is the potential bypass of Secure Boot protections on affected Ubuntu systems. Secure Boot is critical in preventing unauthorized firmware or bootloader code from executing, which helps protect against rootkits, bootkits, and persistent malware. If an attacker gains access to the UEFI Shell, they could execute arbitrary commands or load unsigned code during system startup, undermining system integrity and potentially leading to persistent compromise. For European organizations, especially those in sectors with stringent security requirements such as finance, government, healthcare, and critical infrastructure, this vulnerability could weaken the trusted computing base. Although exploitation requires local access and user interaction, the firmware-level nature of the vulnerability means that successful attacks could be difficult to detect and remediate. The low CVSS score indicates limited risk under typical conditions, but the potential for firmware compromise elevates the importance of timely patching. Organizations relying on Ubuntu systems with affected edk2 versions should consider the risk in their threat models, particularly for devices in sensitive or high-risk environments.

To mitigate CVE-2025-2486, organizations should immediately update Ubuntu edk2 packages to versions 2024.05-2ubuntu0.3 or 2024.02-2ubuntu0.3 or later, which disable the UEFI Shell in Secure Boot environments. Beyond patching, organizations should enforce strict physical security controls to prevent unauthorized local access to systems, as exploitation requires local presence and user interaction. Implementing secure boot policies that verify firmware integrity and restrict boot options can further reduce risk. Regularly audit firmware versions and configurations to ensure compliance with security baselines. Additionally, organizations should monitor for unusual boot-time activity or unauthorized firmware modifications. For environments where Secure Boot is critical, consider deploying hardware-based protections such as TPM and measured boot to enhance firmware security. Finally, maintain awareness of related vulnerabilities and firmware updates from Ubuntu and edk2 projects to promptly address emerging issues.