CVE-2025-20798 is an out-of-bounds write vulnerability classified under CWE-787, discovered in the battery management component of MediaTek chipsets. The root cause is a missing bounds check that allows writing outside the intended memory buffer. This flaw can be exploited by an attacker who already has System-level privileges on the device to escalate their privileges further, potentially gaining higher control over the system. The vulnerability affects a broad range of MediaTek chipsets, including models MT2718 through MT8893, which are commonly integrated into smartphones, tablets, and IoT devices. Exploitation does not require user interaction, which means once an attacker has local system access, they can leverage this vulnerability without additional steps. The CVSS v3.1 score is 7.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and low privileges required. Although no public exploits have been reported yet, the vulnerability poses a significant risk due to the widespread deployment of affected chipsets and the critical nature of battery subsystem operations. The issue was reserved in November 2024 and published in January 2026, with a patch identified as ALPS10315812. The vulnerability's exploitation could lead to system compromise, data leakage, or denial of service by corrupting memory in the battery management process.

The vulnerability allows local attackers with System privileges to perform out-of-bounds writes, potentially leading to arbitrary code execution, privilege escalation, or system instability. This can compromise the confidentiality, integrity, and availability of affected devices. Given the extensive use of MediaTek chipsets in consumer electronics and IoT devices worldwide, exploitation could lead to widespread device compromise, unauthorized data access, and disruption of critical services. Organizations relying on MediaTek-powered devices in their infrastructure or supply chain may face increased risk of targeted attacks. The lack of required user interaction and low attack complexity further increase the threat level. If exploited in sensitive environments, this vulnerability could facilitate lateral movement, persistent access, or sabotage of device functionality.

1. Apply the official patch ALPS10315812 from MediaTek as soon as it becomes available for all affected chipset models. 2. Restrict local System-level access to trusted administrators only, minimizing the risk of an attacker gaining the initial required privileges. 3. Implement strict access controls and monitoring on devices using MediaTek chipsets to detect unusual privilege escalation attempts or memory corruption indicators. 4. Employ runtime protections such as memory protection mechanisms (e.g., DEP, ASLR) where supported by the device firmware to mitigate exploitation impact. 5. For organizations deploying IoT devices with these chipsets, ensure secure device onboarding and firmware update processes to quickly distribute patches. 6. Conduct regular security audits and vulnerability assessments focusing on local privilege escalation vectors. 7. Educate users and administrators about the risks of granting System-level access and encourage the use of least privilege principles.