MediaTek Chipset Vulnerabilities Enable Unauthorized Access

MediaTek has disclosed three critical security vulnerabilities in its August 2025 Product Security Bulletin that affect a wide range of chipsets used in smartphones, tablets, and IoT devices.

These out-of-bounds write vulnerabilities enable local privilege escalation attacks, potentially compromising millions of devices worldwide.

This high-severity vulnerability stems from a missing bounds check that allows out-of-bounds write operations, enabling attackers with physical device access to escalate privileges locally.

The vulnerability requires user interaction but no additional execution privileges, making it particularly concerning for targeted attacks.

The Download Agent plays a crucial role in MediaTek’s flashing and unlocking procedures. It serves as a secure boot authentication mechanism that controls access to device storage during firmware operations.

An exploit of this component could grant attackers deep system access, potentially allowing them to bypass security measures, install malicious firmware, or extract sensitive data.

This vulnerability affects an extensive list of 32 chipsets, including popular models like MT6761, MT6765, MT6877, MT6983, and MT8196.

The impact spans across multiple software versions including Android 13.0, 14.0, and 15.0, as well as openWRT, Yocto, RDK-B, and Zephyr platforms.

MediaTek Chipset Vulnerabilities

Two medium-severity vulnerabilities, CVE-2025-20697 and CVE-2025-20698, target MediaTek Power Hardware Abstraction Layer (HAL) with identical attack vectors.

Both vulnerabilities exploit missing bounds checks that enable out-of-bounds write operations, allowing attackers who have already obtained System-level privileges to escalate further without user interaction.

Key characteristics of these Power HAL vulnerabilities include:

• CVE-2025-20697 affects 28 chipsets including MT6761, MT6765, MT6877, MT6989, and MT8196, specifically targeting devices running Android 14.0 and 15.0.
  
• CVE-2025-20698 impacts 45 chipsets across Android 13.0, 14.0, and 15.0 versions, making it the most widespread vulnerability in this bulletin.
  
• Both vulnerabilities require System-level privileges as a prerequisite but enable silent privilege escalation without user interaction.
  
• The attack vector exploits identical missing bounds checks in the Power HAL component, suggesting a systemic coding issue.
  
• These vulnerabilities provide a pathway for complete device compromise once an attacker gains initial System access through other means.

These Power HAL vulnerabilities are particularly dangerous because they require no user interaction for exploitation.

Once an attacker gains System privileges through other means, these vulnerabilities provide a silent pathway for further privilege escalation, potentially enabling complete device compromise.

Mitigations

MediaTek has proactively notified device Original Equipment Manufacturers (OEMs) at least two months before public disclosure, allowing sufficient time for patch development and distribution.

The most severe vulnerability, CVE-2025-20696, targets MediaTek’s Download Agent (DA) component with a CVSS score of 6.8.

The company emphasizes that it is currently unaware of any active exploitation of these vulnerabilities in the wild.

The vulnerabilities were identified through both internal security research and external security researcher contributions, with CVE-2025-20697 and CVE-2025-20698 being reported by researcher Shiyier.

This collaborative approach to vulnerability disclosure demonstrates MediaTek’s commitment to improving chipset security through responsible disclosure practices.

Out-of-bounds write vulnerabilities like these are classified under CWE-787 and typically result from insufficient input validation.

They can lead to memory corruption, arbitrary code execution, and privilege escalation attacks.

The CVSS scoring system rates these vulnerabilities based on factors including attack complexity, required privileges, and potential impact on confidentiality, integrity, and availability.

Device users should ensure their smartphones and tablets receive the latest security updates from their manufacturers.

Organizations using MediaTek-powered IoT devices should prioritize firmware updates and consider implementing additional network segmentation to limit potential attack vectors.

The widespread nature of these vulnerabilities across multiple chipset families underscores the critical importance of maintaining current security patches across all connected devices.

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