CVE-2025-20705: 
NixOS vulnerability analysis and mitigation

CVE-2025-20705 is a medium-severity use-after-free vulnerability discovered in the monitor_hang component of MediaTek chipsets. The vulnerability was disclosed on September 1, 2025, affecting multiple MediaTek chipset models across various platforms including Android 13.0 through 16.0, OpenWRT 19.07/21.02, and Yocto 2.6. The affected hardware includes numerous chipset models from MT2718 to MT8796 (MediaTek Bulletin).

The vulnerability is classified as CWE-416 (Use After Free) with a CVSS v3.1 base score of 7.8 (HIGH). The issue stems from possible memory corruption due to use-after-free in the monitor_hang component. The vulnerability requires local access and low privileges for exploitation, with no user interaction needed. The attack vector is local (AV:L), with low attack complexity (AC:L) and low privileges required (PR:L) (CISA ADP).

If successfully exploited, this vulnerability could lead to local privilege escalation if an attacker has already obtained System privileges. The impact affects confidentiality, integrity, and availability, all rated as High according to the CVSS scoring (MediaTek Bulletin, Cybersecurity News).

MediaTek has released patches to address this vulnerability and distributed them to OEM partners at least two months prior to public disclosure. Device manufacturers are advised to update their firmware with the provided patches. Users should apply any security updates provided by their device manufacturers to mitigate this vulnerability (GBHackers).

The vulnerability was disclosed as part of MediaTek's September 2025 security bulletin, which included several other security fixes. The disclosure was handled through a coordinated process, with OEM partners receiving patches two months before public announcement, demonstrating MediaTek's commitment to responsible vulnerability disclosure (GBHackers).