CVE-2025-0690: 
Alma Linux vulnerability analysis and mitigation

The vulnerability CVE-2025-0690 affects the read command functionality in GRUB2. Discovered and disclosed on February 18, 2025, this vulnerability involves an integer overflow issue in the keyboard input handling mechanism. The vulnerability affects GRUB2 bootloader systems and was reported by security researcher Jonathan Bar Or (GRUB Disclosure).

The vulnerability stems from an integer overflow condition in the read command's input handling. The read command maintains the input length in a 32-bit integer value, which is used to reallocate the line buffer for accepting new characters. When processing large input lines, this integer value can overflow, leading to an out-of-bounds write in the heap-based buffer. The vulnerability has been assigned a CVSS v3.1 score of 6.1 (CVSS:3.1/AV:P/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H) (Red Hat CVE).

The exploitation of this vulnerability could lead to corruption of GRUB's internal critical data. The potential impact includes the possibility of secure boot bypass, though this would require physical access and high privileges to exploit. Red Hat has rated this vulnerability with Moderate severity due to these requirements (Red Hat CVE).

Fixes for this vulnerability have been made public and incorporated into the GRUB2 codebase. An upstream shim release is planned that will publish updated Sbat (Secure Boot Advanced Targeting) revocations to address older GRUB versions. Organizations should apply the latest security updates when they become available from their respective vendors (GRUB Disclosure).