CVE-2025-20798: 
NixOS vulnerability analysis and mitigation

CVE-2025-20798 is an out-of-bounds write vulnerability in the MediaTek battery subsystem that can enable local escalation of privilege on affected Android devices. It was disclosed by MediaTek on January 5–6, 2026, and affects Android versions 14.0, 15.0, and 16.0 running on a broad range of MediaTek chipsets (MT2718, MT6765, MT6768, MT6781, MT6833, MT6835, MT6853, MT6855, MT6877, MT6879, MT6893, MT6985, MT6989, MT6991, MT8186, MT8188, MT8196, MT8367, MT8391, MT8676, MT8678, MT8696, MT8766, MT8768, MT8781, MT8786, MT8788E, MT8791T, MT8792, MT8793, MT8796, MT8873, MT8883, MT8893). The vulnerability is tracked internally as Patch ID ALPS10315812 and Issue ID MSV-5533. It carries a CVSS v3.1 base score of 7.8 (High) (MediaTek Advisory, Red Hat CVE).

The root cause is a missing bounds check in the battery subsystem driver, classified as CWE-787 (Out-of-bounds Write). An attacker who has already obtained System-level privilege on the device can trigger the out-of-bounds write without any user interaction, making the attack vector local with low attack complexity. The missing validation allows memory beyond the intended buffer boundary to be overwritten, which can be leveraged to escalate privileges further within the kernel or trusted execution environment. No public proof-of-concept or detailed technical write-up has been published as of the disclosure date (MediaTek Advisory, Red Hat CVE).

Successful exploitation results in high impact to confidentiality, integrity, and availability — an attacker with System privilege could gain elevated kernel-level access, enabling unauthorized data access, arbitrary data modification, and potential system disruption. Because the vulnerability resides in a low-level hardware driver, exploitation could facilitate deeper persistence or lateral movement within the device's trust boundaries. The wide chipset scope means a large number of Android 14–16 devices from multiple OEMs (including Lenovo tablets) are potentially affected (MediaTek Advisory, Lenovo Advisory).

There is no evidence of active in-the-wild exploitation or a publicly available proof-of-concept as of the disclosure date. The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of near-term exploitation. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires the attacker to have already obtained System-level privilege on the target device, which significantly raises the bar for exploitation (MediaTek Advisory, Red Hat CVE).

MediaTek has released a patch (Patch ID: ALPS10315812) addressed in the January 2026 MediaTek Product Security Bulletin. Device manufacturers and OEMs should integrate and distribute this patch to affected devices running Android 14.0, 15.0, and 16.0 with the listed chipsets. Lenovo has published a corresponding advisory for affected MediaTek-based tablets. Users should apply OEM firmware updates as soon as they become available, and organizations should prioritize patching devices with elevated-privilege access to sensitive systems (MediaTek Advisory, Lenovo Advisory).

Security news outlet SecurityOnline.info covered the January 2026 MediaTek security bulletin, noting it as a major security overhaul for mobile chipsets. The vulnerability received brief social media attention via TheHackerWire on Mastodon and Bluesky. No significant independent researcher commentary or detailed community analysis has been published (SecurityOnline).