CVE-2025-20766: Android Display Privilege Escalation Flaw

CVE-2025-20766 Overview

CVE-2025-20766 is a high-severity memory corruption vulnerability affecting the display driver component in numerous MediaTek chipsets running Google Android versions 14.0, 15.0, and 16.0. The vulnerability stems from improper input validation in the display subsystem, which can lead to use of uninitialized memory (CWE-457). An attacker who has already obtained System-level privileges can exploit this flaw to achieve local privilege escalation without requiring user interaction.

Critical Impact

Local privilege escalation vulnerability in MediaTek display driver affecting over 30 chipset models across Android 14, 15, and 16 devices. Attackers with System privilege can corrupt memory to gain elevated access.

Affected Products

• Google Android 14.0, 15.0, and 16.0
• MediaTek MT6739, MT6761, MT6765, MT6768, MT6781, MT6789
• MediaTek MT6833, MT6835, MT6853, MT6855, MT6877, MT6878, MT6879
• MediaTek MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899
• MediaTek MT6983, MT6985, MT6989, MT6991
• MediaTek MT2718, MT8196, MT8676, MT8678, MT8792, MT8793

Discovery Timeline

• December 2, 2025 - CVE-2025-20766 published to NVD
• December 3, 2025 - Last updated in NVD database

Technical Details for CVE-2025-20766

Vulnerability Analysis

This vulnerability resides in the display driver component of MediaTek chipsets and is classified under CWE-457 (Use of Uninitialized Variable). The CVSS 3.1 base score is 7.8 (High) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

The vulnerability metrics indicate:

• Attack Vector: Local - requires local access to the device
• Attack Complexity: Low - exploitation does not require specialized conditions
• Privileges Required: Low - attacker needs some level of privilege
• User Interaction: None - no user action required for exploitation
• Impact: High confidentiality, integrity, and availability impact

The Exploit Prediction Scoring System (EPSS) rates this vulnerability with a probability of 0.005% (21.1st percentile), indicating relatively low predicted exploitation in the wild as of December 16, 2025.

Root Cause

The root cause of CVE-2025-20766 is improper input validation within the MediaTek display driver subsystem. When processing display-related operations, the driver fails to adequately validate input parameters before use. This leads to the use of uninitialized memory variables, which can be manipulated by an attacker to corrupt memory structures. The vulnerability is tracked internally by MediaTek as Patch ID ALPS10196993 and Issue ID MSV-4820.

Attack Vector

The attack vector for this vulnerability is local, meaning an attacker must have existing access to the target Android device. Specifically, the attacker must have already obtained System-level privilege on the device before attempting exploitation. Once these prerequisites are met, the attacker can trigger the vulnerability through the display driver interface without requiring any user interaction.

The exploitation flow involves:

1. Attacker gains initial access with System privilege on the target device
2. Attacker sends crafted input to the display driver component
3. The driver processes the input without proper validation
4. Uninitialized memory is used, leading to memory corruption
5. Attacker leverages the corruption to escalate privileges further

The vulnerability mechanism involves improper input validation in the display driver that allows uninitialized memory to be used during processing. This can lead to predictable memory states being exploited by an attacker to manipulate execution flow or corrupt critical data structures. For detailed technical information, refer to the MediaTek Product Security Bulletin for December 2025.

Detection Methods for CVE-2025-20766

Indicators of Compromise

• Unexpected crashes or system instability in display-related processes
• Anomalous behavior in processes interacting with the MediaTek display driver
• Evidence of privilege escalation attempts from System-level processes
• Unusual memory access patterns in display driver kernel logs

Detection Strategies

Organizations and security teams should implement monitoring for suspicious activity related to the display subsystem on affected MediaTek-based Android devices. Key detection approaches include:

1. Kernel Log Monitoring: Monitor kernel logs (dmesg) for display driver errors, crashes, or warnings that may indicate exploitation attempts
2. Process Monitoring: Track processes with System privileges that interact with display drivers for unusual behavior
3. Behavioral Analysis: Implement endpoint detection solutions capable of identifying privilege escalation patterns
4. Integrity Monitoring: Monitor for unauthorized changes to system components or unexpected privilege elevations

Monitoring Recommendations

Security teams managing fleets of Android devices with MediaTek chipsets should:

• Enable detailed logging on affected devices where possible
• Deploy mobile threat detection solutions capable of detecting privilege escalation
• Monitor for security patches and ensure timely application
• Implement application whitelisting and restrict applications that can gain System privileges
• Use SentinelOne Mobile Threat Defense to detect exploitation attempts and anomalous behavior on managed Android devices

How to Mitigate CVE-2025-20766

Immediate Actions Required

• Apply the December 2025 security patch from MediaTek immediately on all affected devices
• Restrict physical access to affected devices pending patch application
• Audit and minimize applications with System-level privileges
• Enable mobile device management (MDM) policies to enforce timely security updates
• Monitor affected devices for signs of compromise using endpoint detection tools

Patch Information

MediaTek has released a security patch to address this vulnerability, tracked as Patch ID ALPS10196993. The patch is documented in the MediaTek Product Security Bulletin for December 2025. Device manufacturers integrating MediaTek chipsets should incorporate this patch into their firmware updates. End users should apply Android security updates as they become available from their device manufacturers.

Workarounds

There are no official workarounds provided by MediaTek for this vulnerability. The recommended mitigation is to apply the security patch as soon as it becomes available from your device manufacturer. In the interim, organizations should:

• Limit the installation of untrusted applications that could be used to gain initial System privilege
• Implement strict device management policies to control application installations
• Consider network isolation for high-risk devices until patches can be applied
• Use mobile threat defense solutions to detect and respond to exploitation attempts

Organizations deploying SentinelOne can leverage the platform's mobile protection capabilities to detect anomalous behavior patterns associated with privilege escalation attempts on Android devices.