CVE-2025-20777 Overview
CVE-2025-20777 is an out-of-bounds write vulnerability in the MediaTek display component used across a broad range of MediaTek chipsets running Google Android 14, 15, and 16. The flaw stems from a missing bounds check that allows a local attacker to write beyond an allocated buffer. Successful exploitation can lead to local privilege escalation, but only after the attacker has already obtained System privileges. No user interaction is required. MediaTek tracks the fix under Patch ID ALPS10184870 and Issue ID MSV-4752.
Critical Impact
An attacker already running with System privileges can leverage the missing bounds check in the display driver to write out of bounds and escalate further on affected MediaTek-powered Android devices.
Affected Products
- Google Android 14.0, 15.0, and 16.0
- MediaTek smartphone SoCs including MT6739, MT6761, MT6765, MT6768, MT6781, MT6789, MT6833, MT6835, MT6853, MT6855, MT6877, MT6878, MT6879, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899, MT6983, MT6985, MT6989, and MT6991
- MediaTek tablet and embedded SoCs including MT8186, MT8188, MT8196, MT8667, MT8673, MT8676, MT8678, MT8765, MT8766, MT8768, MT8771, MT8781, MT8791T, MT8792, MT8793, MT8795T, MT8796, MT8798, MT8873, and MT8883
Discovery Timeline
- 2025-12-02 - CVE-2025-20777 published to NVD
- 2025-12-03 - Last updated in NVD database
Technical Details for CVE-2025-20777
Vulnerability Analysis
The vulnerability resides in the MediaTek display component shipped with affected Android builds. A missing bounds check on data passed to a write operation allows the code path to access memory beyond the bounds of the target buffer. This is a classic out-of-bounds write condition tracked under [CWE-787]. Because the display subsystem runs in a privileged context, corruption of adjacent memory can be steered to alter kernel or driver state, enabling local escalation of privilege. MediaTek addressed the issue in Patch ID ALPS10184870 (Issue ID MSV-4752) as part of the December 2025 MediaTek Product Security Bulletin.
Root Cause
The root cause is the absence of a length or index validation before a memory write in the MediaTek display driver. When attacker-controlled input drives the write index or size, the operation reaches memory regions outside the intended allocation. The lack of validation lets the driver perform a write whose effects depend on adjacent kernel or driver structures.
Attack Vector
The attack vector is local. An attacker must already hold System privilege on the device to reach the vulnerable interface in the display component. From that position, the attacker triggers the unchecked write path to corrupt adjacent memory and pivot toward higher privileges within the device. No user interaction is required, and the attack is confined to a single device.
No public proof-of-concept code or exploit has been released for CVE-2025-20777. Technical specifics of the vulnerable function are not disclosed in the MediaTek Security Bulletin December 2025.
Detection Methods for CVE-2025-20777
Indicators of Compromise
- No public indicators of compromise have been published for CVE-2025-20777.
- Unexpected crashes, kernel panics, or tombstone entries referencing MediaTek display driver paths on affected devices may warrant investigation.
- Presence of unauthorized apps or services already running with System privileges, which is a prerequisite for exploitation.
Detection Strategies
- Inventory mobile fleet devices and identify those using affected MediaTek SoCs running Android 14, 15, or 16 without the December 2025 patch level.
- Use mobile device management (MDM) attestation and Android security patch level reporting to flag devices missing the fix that includes Patch ID ALPS10184870.
- Monitor for privilege escalation chains on managed Android devices, since this issue requires an attacker that already holds System rights.
Monitoring Recommendations
- Track Android Security Patch Level (ro.build.version.security_patch) across enrolled devices and alert on devices behind the December 2025 baseline.
- Correlate device crash telemetry with MediaTek display driver stack frames to surface anomalous write faults.
- Review MDM compliance dashboards for devices that cannot receive vendor updates and prioritize them for replacement or restricted access.
How to Mitigate CVE-2025-20777
Immediate Actions Required
- Apply the December 2025 MediaTek security patch on all affected devices as soon as the OEM build is available.
- Confirm the Android Security Patch Level on each device reflects the December 2025 update after deployment.
- Restrict installation of untrusted applications and limit which processes can run with elevated privileges on managed devices.
Patch Information
MediaTek issued the fix under Patch ID ALPS10184870, tracked as Issue ID MSV-4752, and documented it in the MediaTek Security Bulletin December 2025. Device OEMs integrate this fix into their monthly Android security updates. End users and administrators should install the latest vendor update for their specific device model.
Workarounds
- No official vendor workaround is published. Patching remains the only supported remediation.
- Enforce MDM policies that block sideloaded applications and require attestation before granting access to sensitive corporate resources.
- Retire or isolate end-of-life devices that will not receive the December 2025 MediaTek patch.
# Verify Android security patch level on a connected device
adb shell getprop ro.build.version.security_patch
# Expected output should be 2025-12-01 or later for affected MediaTek devices
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
