CVE-2023-20695: 
NixOS vulnerability analysis and mitigation

CVE-2023-20695 is a high-severity vulnerability discovered in MediaTek's preloader component. The vulnerability was disclosed in May 2023 and affects various MediaTek chipsets including MT6835, MT6880, MT6886, MT6890, MT6980, MT6985, MT6990, and several others in the MT81xx series. The vulnerability stems from a missing bounds check that could lead to an out-of-bounds write condition (MediaTek Bulletin).

The vulnerability is classified as an improper input validation issue (CWE-20) that manifests as an out-of-bounds write condition in the preloader component. It has been assigned a CVSS v3.1 base score of 6.7 (Medium), with the vector string CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. The vulnerability requires system execution privileges for exploitation, and no user interaction is needed (NVD).

If exploited, this vulnerability could lead to local escalation of privilege with System execution privileges. The vulnerability affects devices running Android 13.0 and OpenWrt versions 19.07 and 21.02 (MediaTek Bulletin).

The vulnerability requires local access and system execution privileges for exploitation. No user interaction is needed for exploitation, making it potentially attractive to attackers who already have a foothold on the system (MediaTek Bulletin).

MediaTek has addressed this vulnerability through patches identified as ALPS07734012 / ALPS07874363, specifically for MT6880, MT6890, MT6980, and MT6990 chipsets. Device manufacturers have been notified of the security patches at least two months before the public disclosure (MediaTek Bulletin).