CVE-2025-20769 is a stack overflow vulnerability classified under CWE-121, identified in various 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, MT8196, MT8676, MT8678, MT8792, and MT8793. These chipsets are integrated into Android devices running versions 14.0 through 16.0. The vulnerability stems from a missing bounds check in the display subsystem, which allows an out-of-bounds write on the stack. This flaw can be exploited locally by an attacker who already possesses System-level privileges, enabling escalation of privileges further within the device. No user interaction is required, which increases the risk of automated or stealthy exploitation. The vulnerability could lead to arbitrary code execution or corruption of critical memory areas, compromising system integrity and potentially availability. Although no public exploits have been reported, the broad range of affected chipsets and Android versions indicates a significant attack surface. The issue was reserved in November 2024 and published in December 2025, with patches referenced by MediaTek under internal IDs but no public patch links currently available. The vulnerability does not have an assigned CVSS score, but its characteristics suggest a high severity level due to the potential impact and ease of exploitation once System privileges are obtained.

For European organizations, this vulnerability poses a significant risk primarily to mobile devices using affected MediaTek chipsets. Many enterprises rely on smartphones for secure communications, authentication, and access to corporate resources. Exploitation could allow attackers with System privileges to escalate their access, potentially leading to full device compromise, data leakage, or disruption of device functionality. This could undermine confidentiality, integrity, and availability of sensitive information accessed or stored on these devices. The lack of required user interaction facilitates stealthy attacks, increasing the risk of unnoticed compromise. Organizations with Bring Your Own Device (BYOD) policies or those deploying MediaTek-based devices in their infrastructure are particularly vulnerable. The vulnerability could also impact mobile device management (MDM) solutions and secure applications relying on the integrity of the underlying hardware and OS. The broad range of affected chipsets means that many consumer and enterprise devices across Europe could be impacted, necessitating urgent attention to patching and device security controls.

1. Apply vendor-supplied patches immediately once available to remediate the vulnerability in affected MediaTek chipsets. 2. Enforce strict device management policies to limit the installation of untrusted applications that could gain System privileges. 3. Implement runtime protections such as stack canaries, address space layout randomization (ASLR), and control flow integrity (CFI) where possible to mitigate exploitation impact. 4. Monitor devices for unusual behavior indicative of privilege escalation attempts, including unexpected system-level process activity. 5. Restrict physical and logical access to devices to prevent attackers from obtaining System privileges initially. 6. Educate users and administrators about the risks of privilege escalation vulnerabilities and the importance of timely updates. 7. Use mobile threat defense (MTD) solutions that can detect exploitation attempts or anomalous device behavior. 8. For organizations deploying custom Android builds, review and harden display subsystem code to prevent similar out-of-bounds writes. 9. Coordinate with device vendors and carriers to ensure rapid deployment of security updates across the device fleet.