CVE-2025-20797: 
NixOS vulnerability analysis and mitigation

CVE-2025-20797 is an out-of-bounds write vulnerability in the battery driver component of MediaTek chipsets, allowing 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 SoCs including 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, and MT8893. The vulnerability carries a CVSS v3.1 base score of 7.8 (High), assessed by CISA-ADP (MediaTek Bulletin, NVD).

The root cause is a missing bounds check in the battery driver, classified as CWE-121 (Stack-based Buffer Overflow) by MediaTek and CWE-787 (Out-of-bounds Write) by NIST, enabling a stack-based out-of-bounds write condition (NVD, MediaTek Bulletin). The attack vector is local, requires low privileges (System-level access already obtained), low attack complexity, and no user interaction. An attacker who has already achieved System privilege can trigger the memory corruption to further escalate privileges within the device. The patch is identified as ALPS10315812 (Issue ID: MSV-5534) (MediaTek Bulletin).

Successful exploitation allows a local attacker who already holds System privilege to escalate further, with high impact to confidentiality, integrity, and availability of the affected device. This could enable access to sensitive data, modification of system state, or disruption of device functionality. The broad scope of affected MediaTek chipsets means a large number of Android 14, 15, and 16 devices — including smartphones and tablets from multiple OEMs — are potentially at risk (MediaTek Bulletin, NVD).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation as of the time of disclosure (Feedly). The EPSS score is approximately 0.018% (0.000180), indicating a very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires the attacker to have already obtained System-level privileges on the device, which significantly limits the practical attack surface.

MediaTek has released a patch (Patch ID: ALPS10315812; Issue ID: MSV-5534) addressed in the MediaTek Product Security Bulletin for January 2026. Device manufacturers and OEMs should integrate and distribute this patch to affected devices running Android 14.0, 15.0, and 16.0 on the listed MediaTek chipsets. Lenovo has also published a specific advisory for affected MediaTek-based tablet products (Lenovo Advisory). Organizations should audit their device inventory for affected MediaTek SoCs and prioritize applying OEM security updates as they become available (MediaTek Bulletin).

The vulnerability received coverage from security news outlets such as SecurityOnline.info, which highlighted MediaTek's January 2026 security overhaul for mobile chipsets (SecurityOnline). TheHackerWire noted the disclosure on social platforms including Mastodon and Bluesky. Lenovo issued a dedicated vendor advisory for its MediaTek-based tablet lineup, reflecting OEM-level response to the bulletin (Lenovo Advisory). Overall community reaction was measured, consistent with the absence of active exploitation.