CVE-2025-20749 is a stack-based buffer overflow vulnerability (CWE-121) identified in the charger component of a broad range of MediaTek System on Chips (SoCs), including MT6789, MT6835, MT6855, MT6878, MT6879, MT6886, MT6897, MT6899, MT6983, MT6985, MT6989, MT6991, MT8169, MT8188, MT8195, MT8196, MT8781, and MT8796. The flaw results from a missing bounds check during a write operation, causing an out-of-bounds write on the stack. This vulnerability can be exploited locally by an attacker who has already obtained System-level privileges on the device, enabling escalation to higher privileges or potentially compromising system integrity. No user interaction is required for exploitation, increasing the risk in environments where System privileges are already compromised. The affected devices run Android versions 14.0 through 16.0, indicating this vulnerability impacts recent and upcoming Android releases on MediaTek platforms. 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. While no public exploits are known at this time, the vulnerability poses a significant risk in chained attacks or insider threat scenarios. The issue has been assigned patch ID ALPS09915493 and issue ID MSV-3800 by MediaTek, but no public patch links are currently available. Organizations should monitor for patches and advisories from MediaTek and device manufacturers.

The primary impact of CVE-2025-20749 is local privilege escalation on devices using affected MediaTek SoCs running Android 14.0 to 16.0. An attacker with System-level privileges can exploit this vulnerability to gain higher privileges, potentially leading to full device compromise. This could allow unauthorized access to sensitive data, modification or deletion of critical system files, installation of persistent malware, or disruption of device availability. Since the vulnerability affects a wide range of MediaTek chipsets commonly used in smartphones, tablets, and IoT devices, the scope of impact is broad. Enterprises relying on these devices for communication or operational purposes could face data breaches or operational disruptions. The lack of required user interaction increases the risk in environments where attackers have already gained partial access. Although no exploits are currently known in the wild, the vulnerability could be leveraged in targeted attacks or combined with other exploits to bypass security controls. This elevates the threat level for organizations with high-value targets or sensitive data on affected devices.

1. Apply official patches from MediaTek or device manufacturers as soon as they become available to address the missing bounds check and prevent out-of-bounds writes. 2. Implement strict privilege separation and minimize the number of processes or users with System-level privileges to reduce the attack surface. 3. Employ runtime protections such as stack canaries, address space layout randomization (ASLR), and control flow integrity (CFI) on affected devices to mitigate exploitation attempts. 4. Monitor device logs and behavior for signs of privilege escalation or anomalous activity indicative of exploitation attempts. 5. Restrict installation of untrusted applications and enforce application whitelisting to prevent attackers from gaining initial System privileges. 6. For enterprise environments, consider mobile device management (MDM) solutions to enforce security policies and expedite patch deployment. 7. Educate users and administrators about the risks of privilege escalation vulnerabilities and the importance of timely updates. 8. Conduct regular security assessments and penetration testing focusing on privilege escalation vectors in devices using MediaTek chipsets.