CVE-2025-20766: Android Display Privilege Escalation Flaw

CVE-2025-20766 Overview

CVE-2025-20766 is a memory corruption vulnerability in the MediaTek display component caused by improper input validation. The flaw affects a broad range of MediaTek chipsets used in Android devices running versions 14, 15, and 16. A local attacker who has already obtained System privilege can trigger the issue to escalate privileges further on the device. Exploitation does not require user interaction. MediaTek tracks this issue as Patch ID ALPS10196993 and Issue ID MSV-4820. The vulnerability is categorized under CWE-457: Use of Uninitialized Variable.

Critical Impact
Local privilege escalation in the MediaTek display driver enables an attacker with System privilege to corrupt memory and compromise device integrity across dozens of MediaTek SoC models.

Affected Products

Google Android 14, 15, and 16
MediaTek chipsets: MT2718, MT6739, MT6761, MT6765, MT6768, MT6781, MT6789, MT6833, MT6835, MT6853, MT6855, MT6877, MT6878, MT6879, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899
Additional MediaTek SoCs: MT6983, MT6985, MT6989, MT6991, MT8196, MT8676, MT8678, MT8792, MT8793

Discovery Timeline

2025-12-02 - CVE-2025-20766 published to NVD
2025-12-03 - Last updated in NVD database
December 2025 - MediaTek publishes Product Security Bulletin with patch ALPS10196993

Technical Details for CVE-2025-20766

Vulnerability Analysis

The vulnerability resides in the MediaTek display subsystem on Android devices. Improper input validation in the display component allows attacker-controlled data to corrupt memory during processing. The issue maps to [CWE-457: Use of Uninitialized Variable], indicating that the display driver consumes memory contents without validating that the source data was properly initialized.

MediaTek classifies the flaw as a local elevation-of-privilege vulnerability requiring pre-existing System privilege. While this raises the exploitation bar, attackers who chain this vulnerability with a less-privileged initial foothold can bridge from System context to higher-privilege kernel or driver execution. The display driver typically runs with elevated permissions on Android, making it an attractive target for post-compromise escalation chains.

Root Cause

The root cause is missing or insufficient validation of input data passed to the display component, combined with use of uninitialized values during memory operations. When the driver processes an attacker-supplied input, memory regions are referenced or written without proper bounds or initialization checks. This produces corruption of adjacent kernel or driver memory structures.

Attack Vector

Exploitation requires local access with System-level privileges on the device. An attacker who has already compromised a System-privileged process — for example, through a separate Android application sandbox escape — can interact with the vulnerable display interface to trigger the memory corruption. No user interaction is required. The vulnerability is not remotely exploitable, and there are no public proof-of-concept exploits or CISA KEV entries at the time of publication.

The display driver attack surface on MediaTek devices is exposed through ioctl calls and device nodes accessible to privileged system services. Successful exploitation enables attackers to subvert kernel-level controls, install persistent rootkits, or disable security mitigations.

Detection Methods for CVE-2025-20766

Indicators of Compromise

Unexpected crashes or kernel panics referencing MediaTek display driver modules in dmesg or logcat output
Anomalous ioctl invocations against display device nodes from non-display system processes
Presence of unsigned or modified kernel modules following privileged process activity
Unexpected escalations from system_server or other System-context processes to kernel-level operations

Detection Strategies

Monitor Android device build fingerprints and patch levels to confirm December 2025 MediaTek bulletin patches are applied
Inspect mobile device management (MDM) telemetry for devices reporting outdated patch levels on affected MediaTek SoCs
Correlate application installation events with subsequent privileged process anomalies to identify chained exploitation attempts

Monitoring Recommendations

Enforce Android security patch level reporting through enterprise mobility management platforms
Alert on devices running affected MediaTek chipsets that have not received the December 2025 security update
Track installation of applications requesting display-related permissions or interacting with display device nodes

How to Mitigate CVE-2025-20766

Immediate Actions Required

Apply the MediaTek December 2025 security patch (ALPS10196993) as distributed by the device OEM
Update affected Android devices to the December 2025 Android Security Patch Level or later
Identify the inventory of affected MediaTek chipsets in your fleet using device telemetry
Restrict installation of untrusted applications on devices pending patch deployment

Patch Information

MediaTek has released a fix referenced by Patch ID ALPS10196993 and Issue ID MSV-4820. Device OEMs incorporate the patch into the monthly Android Security Patch Level. Refer to the MediaTek Product Security Bulletin — December 2025 for the complete advisory and chipset coverage.

Workarounds

No vendor-supplied workaround exists; patching is the only effective remediation
Reduce attack surface by limiting which applications can reach System-privileged services through Android's permission model
Enforce strict application allowlisting via mobile device management on managed Android fleets
Disable sideloading and require Google Play Protect to be active on managed devices

bash

# Verify Android security patch level on a managed device
adb shell getprop ro.build.version.security_patch

# Confirm MediaTek SoC model to determine affected status
adb shell getprop ro.hardware
adb shell getprop ro.board.platform