CVE-2025-20698 is a security vulnerability classified as CWE-787 (Out-of-bounds Write) found in the Power Hardware Abstraction Layer (HAL) of numerous MediaTek chipsets, including MT2718, MT6739, MT6761, MT6765, MT6768, MT6781, MT6789, MT6833, MT6835, MT6853, MT6855, MT6877, MT6878, MT6879, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899, MT6983, MT6985, MT6989, MT6991, MT8186, MT8196, MT8391, MT8676, MT8678, MT8775, MT8786, MT8788E, MT8792, MT8796, MT8873, MT8883, and MT8893. These chipsets are integrated into Android devices running versions 13.0, 14.0, and 15.0. The vulnerability stems from a missing bounds check in the Power HAL, which allows an out-of-bounds write operation. This flaw can be exploited by a local attacker who already possesses System-level privileges to escalate their privileges further, potentially gaining higher control over the device. Notably, exploitation does not require any user interaction, increasing the risk in environments where an attacker has local access. The CVSS v3.1 base score is 6.7 (medium severity), with vector AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local attack vector, low attack complexity, high privileges required, no user interaction, unchanged scope, and high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the vulnerability represents a significant risk due to the broad range of affected chipsets and Android versions. The issue was assigned the internal MediaTek patch ID ALPS09915400 and issue ID MSV-3793. The vulnerability highlights the criticality of proper bounds checking in low-level system components such as HAL to prevent memory corruption and privilege escalation.

The impact of CVE-2025-20698 is significant for organizations and individuals using devices with affected MediaTek chipsets. Successful exploitation allows a local attacker with System privileges to perform out-of-bounds writes, leading to escalation of privileges beyond the System level. This can result in full compromise of device confidentiality, integrity, and availability, enabling attackers to execute arbitrary code, access sensitive data, or disrupt device functionality. Given the widespread use of MediaTek chipsets in many Android smartphones, tablets, and IoT devices, the vulnerability poses a broad risk. Enterprises relying on mobile devices for sensitive operations could face data breaches or device takeovers. The lack of required user interaction increases the likelihood of exploitation in environments where attackers have local access, such as through malicious apps or compromised insiders. Although exploitation requires high privileges, the vulnerability can be chained with other flaws to achieve initial access, amplifying the threat. The absence of known exploits in the wild currently limits immediate risk, but the availability of patches and public disclosure may prompt attackers to develop exploits. Overall, the vulnerability threatens device security, user privacy, and organizational data protection, especially in regions with high MediaTek device penetration.

To mitigate CVE-2025-20698, organizations and users should promptly apply official patches released by device manufacturers and MediaTek once available. Since the vulnerability requires System-level privileges for exploitation, enforcing strict access controls to prevent unauthorized elevation to System privileges is critical. Employ mobile device management (MDM) solutions to monitor and restrict installation of untrusted applications that could gain local access. Implement runtime protections such as SELinux policies and integrity checks to detect and prevent abnormal behavior in the Power HAL or related components. Regularly audit devices for signs of privilege escalation attempts or memory corruption. For developers and vendors, conduct thorough code reviews focusing on bounds checking in hardware abstraction layers and low-level system components. Employ fuzz testing and static analysis tools to detect out-of-bounds write vulnerabilities early in the development lifecycle. Finally, educate users and administrators about the risks of granting elevated privileges to applications and the importance of timely updates.