CVE-2025-20777: Android Display Privilege Escalation Flaw

CVE-2025-20777 Overview

CVE-2025-20777 is a medium-severity out-of-bounds write vulnerability affecting the display driver component in Google Android devices utilizing MediaTek chipsets. The vulnerability exists due to a missing bounds check in the display subsystem, which could allow an attacker who has already obtained System-level privileges to escalate their access further. Notably, no user interaction is required for exploitation, making this vulnerability particularly concerning for enterprise device deployments.

The vulnerability has been assigned a CVSS score of 6.7 (Medium) with the vector string CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating high impact on confidentiality, integrity, and availability despite requiring high privileges for initial access.

Critical Impact

Local privilege escalation from System-level access affecting a wide range of MediaTek-powered Android devices across smartphones, tablets, and IoT platforms.

Affected Products

• Google Android 14.0, 15.0, and 16.0
• MediaTek MT67xx Series (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)
• MediaTek MT81xx/MT87xx Series (MT8186, MT8188, MT8196, MT8667, MT8673, MT8676, MT8678, MT8765, MT8766, MT8768, MT8771, MT8781, MT8791T, MT8792, MT8793, MT8795T, MT8796, MT8798, MT8873, MT8883)

Discovery Timeline

• December 2, 2025 - CVE-2025-20777 published to NVD
• December 3, 2025 - Last updated in NVD database

Technical Details for CVE-2025-20777

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write), a memory corruption flaw that occurs when software writes data past the end or before the beginning of an intended buffer. In the context of CVE-2025-20777, the display driver fails to properly validate buffer boundaries when processing display-related operations.

The CVSS vector breakdown reveals:

• Attack Vector (AV:L): Local access required - the attacker must have access to the device
• Attack Complexity (AC:L): Low complexity - exploitation is straightforward once prerequisites are met
• Privileges Required (PR:H): High privileges needed - attacker must already have System-level access
• User Interaction (UI:N): None required - no victim interaction needed
• Scope (S:U): Unchanged - impact limited to the vulnerable component's scope
• Impact (C:H/I:H/A:H): High impact on confidentiality, integrity, and availability

The Exploit Prediction Scoring System (EPSS) indicates a 0.005% probability of exploitation, placing this vulnerability in the 24.3rd percentile as of December 16, 2025.

Root Cause

The root cause of CVE-2025-20777 stems from insufficient bounds checking within the display driver component. When the driver processes certain display-related data structures or commands, it fails to validate that write operations remain within allocated buffer boundaries. This oversight allows an attacker with System privileges to manipulate memory regions beyond the intended buffer, potentially corrupting adjacent memory structures or injecting malicious code.

The vulnerability is tracked internally by MediaTek under Patch ID ALPS10184870 and Issue ID MSV-4752.

Attack Vector

Exploitation of this vulnerability requires an attacker to first obtain System-level privileges on the target Android device. This could be achieved through:

1. Prior exploitation chain: Using another vulnerability to gain initial System access
2. Malicious privileged application: An application that has been granted System privileges (common in rooted or compromised devices)
3. Physical access: Direct device access with debugging capabilities enabled

Once System privileges are obtained, the attacker can trigger the out-of-bounds write condition in the display driver by crafting specific display-related operations or commands that exploit the missing bounds check. The memory corruption resulting from this out-of-bounds write could then be leveraged to:

• Execute arbitrary code in a higher privilege context
• Modify kernel memory structures
• Bypass security mechanisms
• Establish persistent access to the device

Detection Methods for CVE-2025-20777

Indicators of Compromise

• Unexpected crashes or reboots related to display driver components
• Anomalous memory allocation patterns in system logs associated with MediaTek display services
• Suspicious privilege escalation events following display-related operations
• Modified or corrupted display driver binaries or configurations

Detection Strategies

Organizations should implement multi-layered detection strategies to identify potential exploitation attempts:

Kernel-Level Monitoring: Monitor for suspicious interactions with the display driver subsystem, particularly operations that result in memory access violations or unexpected behavior.

Behavioral Analysis: Implement endpoint detection solutions that can identify unusual privilege escalation patterns, especially those originating from display-related processes.

Android Security Logging: Enable verbose logging for system components and monitor for MediaTek display driver exceptions or errors that could indicate exploitation attempts.

Memory Integrity Monitoring: Utilize runtime memory protection mechanisms to detect out-of-bounds write attempts in kernel space.

Monitoring Recommendations

SentinelOne Singularity provides comprehensive protection against exploitation attempts targeting CVE-2025-20777 through:

• Behavioral AI Engine: Detects anomalous process behavior and privilege escalation attempts in real-time
• Memory Protection: Identifies and blocks out-of-bounds memory operations characteristic of this vulnerability class
• Storyline Technology: Correlates related security events to provide full attack context and chain visibility
• Mobile Threat Defense: Extends protection to Android devices, monitoring for driver-level exploitation attempts

Organizations should configure alerts for:

• Display driver crashes or unexpected terminations
• System-level privilege acquisition events
• Memory corruption indicators in kernel logs
• Unusual display subsystem activity patterns

How to Mitigate CVE-2025-20777

Immediate Actions Required

• Apply the MediaTek security patch (ALPS10184870) through your device manufacturer's update channel
• Update affected Android devices to the latest available security patch level
• Review and restrict applications with System-level privileges
• Enable Android Verified Boot to detect unauthorized system modifications
• Implement mobile device management (MDM) solutions to enforce security policies

Patch Information

MediaTek has released a security patch addressing this vulnerability, documented in their December 2025 Product Security Bulletin. The patch implements proper bounds checking in the display driver component to prevent out-of-bounds write operations.

Patch Reference:

• Patch ID: ALPS10184870
• Issue ID: MSV-4752
• Advisory: MediaTek Product Security Bulletin - December 2025

Device manufacturers (OEMs) are responsible for integrating this patch into their Android builds and distributing updates to end users. Contact your device manufacturer for specific patch availability timelines.

Workarounds

If immediate patching is not possible, organizations should implement the following compensating controls:

• Restrict System-Level Access: Audit and minimize applications with System privileges
• Enable SELinux Enforcing Mode: Ensure SELinux remains in enforcing mode to limit exploitation impact
• Implement Application Allowlisting: Only permit approved applications to run on managed devices
• Network Segmentation: Isolate potentially vulnerable devices from sensitive network resources
• Enhanced Monitoring: Increase logging verbosity and monitoring frequency for affected device types

# Verify SELinux status on Android devices via ADB
adb shell getenforce

# Check current security patch level
adb shell getprop ro.build.version.security_patch

# List applications with System privileges for audit
adb shell pm list packages -f | grep /system/