CVE-2025-0622: 
Linux Debian vulnerability analysis and mitigation

A critical vulnerability (CVE-2025-0622) was discovered in GRUB2's command/gpg module, identified on February 18, 2025. The flaw affects the hook management system when modules are unloaded, potentially impacting systems using GRUB2 bootloader (Ubuntu Security, OSS Security).

The vulnerability stems from a scenario where hooks created by loaded modules are not properly removed during module unload operations. This creates a use-after-free condition when GRUB2 attempts to call hooks after their associated module has been unloaded. The vulnerability has been assigned a CVSS 3.1 score of 6.4 (Medium) with the vector string CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local access requirements with high complexity and privilege requirements (OSS Security).

If successfully exploited, this vulnerability could result in arbitrary code execution, potentially allowing attackers to bypass secure boot protections. The high severity impact affects system confidentiality, integrity, and availability, particularly concerning boot security mechanisms (Security Online).

Ubuntu has initiated security evaluations across multiple versions of the grub2-signed and grub2-unsigned packages. The vulnerability requires updates to GRUB2 components and may need key revocation to protect against potential attacks. System administrators are advised to apply updates as they become available from their respective vendors (Ubuntu Security).