CVE-2022-3775: 
vulnerability analysis and mitigation

CVE-2022-3775 is a vulnerability discovered in GRUB2's font code that was disclosed on December 19, 2022. The vulnerability occurs when rendering certain Unicode sequences, where the code fails to properly validate the font width and height constraints within bitmap size. This flaw affects various versions of GRUB2 across multiple operating systems (NVD, Ubuntu).

The vulnerability is classified with a CVSS 3.1 base score of 7.1 (High), with the following characteristics: Local attack vector, Low attack complexity, Low privileges required, No user interaction needed, Unchanged scope, No impact on confidentiality, but High impact on both integrity and availability. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H (Ubuntu).

When exploited, this vulnerability can lead to an out-of-bounds write into GRUB2's heap, resulting in memory corruption and availability issues. While the exploitation is considered complex, the possibility of arbitrary code execution cannot be completely ruled out. The vulnerability primarily affects system availability and integrity (Ubuntu).

Multiple vendors have released patches to address this vulnerability. Ubuntu has fixed the issue in various versions including 22.04 LTS (version 1.187.3~22.04.1), 20.04 LTS (version 1.187.3~20.04.1), and 18.04 LTS (version 1.187.3~18.04.1). Gentoo users are advised to upgrade to GRUB version 2.06-r4 or later (Ubuntu, Gentoo).