CVE-2025-20767: Android Display Privilege Escalation Flaw

CVE-2025-20767 Overview

CVE-2025-20767 is a high-severity integer overflow vulnerability affecting the display driver component in Google Android devices running on MediaTek chipsets. The vulnerability exists in the display subsystem where an integer overflow condition can lead to an out-of-bounds write, potentially allowing an attacker who has already obtained System privileges to escalate to higher privilege levels. This vulnerability requires no user interaction to exploit, making it particularly dangerous in scenarios where an attacker has already compromised the device at the system level.

Critical Impact

Local privilege escalation from System privilege level through integer overflow in display driver, affecting over 30 MediaTek chipset models across Android 14.0, 15.0, and 16.0

Affected Products

• Google Android 14.0, 15.0, and 16.0
• MediaTek MT6700 series chipsets (MT6739, MT6761, MT6765, MT6768, MT6781, MT6789)
• MediaTek MT6800 series chipsets (MT6833, MT6835, MT6853, MT6855, MT6877, MT6878, MT6879, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899)
• MediaTek MT6900 series chipsets (MT6983, MT6985, MT6989, MT6991)
• MediaTek MT8000 series chipsets (MT8196, MT8676, MT8678, MT8792, MT8793)
• MediaTek MT2718

Discovery Timeline

• 2025-12-02 - CVE-2025-20767 published to NVD
• 2025-12-03 - Last updated in NVD database

Technical Details for CVE-2025-20767

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write) and carries a CVSS 3.1 base score of 7.8, indicating high severity. The CVSS vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H reveals several important characteristics:

• Attack Vector (AV:L): Local access is required to exploit this vulnerability
• Attack Complexity (AC:L): The attack is straightforward to execute once prerequisites are met
• Privileges Required (PR:L): Low privilege level is required, though the description notes System privilege is needed
• User Interaction (UI:N): No user interaction is necessary
• Impact: High impact on Confidentiality, Integrity, and Availability

The vulnerability has an EPSS (Exploit Prediction Scoring System) score of 0.005%, placing it in the 21.1st percentile for likelihood of exploitation in the wild.

Root Cause

The root cause of CVE-2025-20767 lies in improper integer handling within the MediaTek display driver. When processing certain display-related operations, the driver fails to properly validate or handle integer arithmetic operations, leading to an integer overflow condition. This overflow causes the calculated buffer size or index to wrap around to a smaller value than expected, resulting in subsequent memory operations writing beyond the allocated buffer boundaries.

The vulnerability is tracked internally by MediaTek under Patch ID ALPS10196993 and Issue ID MSV-4807. The integer overflow specifically occurs in display subsystem operations, suggesting the vulnerable code path is related to display buffer management, framebuffer operations, or display configuration handling.

Attack Vector

The attack vector for CVE-2025-20767 requires local access to the device and System-level privileges as a prerequisite. An attacker who has already compromised the device at the System privilege level can exploit this vulnerability to achieve further privilege escalation.

The exploitation flow involves triggering the integer overflow in the display driver through crafted input or parameters that cause arithmetic overflow during size calculations. When the overflow occurs, the resulting out-of-bounds write can overwrite critical kernel memory structures, potentially allowing the attacker to:

1. Corrupt adjacent memory structures to manipulate kernel data
2. Overwrite function pointers to redirect execution flow
3. Escape from System privilege level to gain kernel-level access

Since no user interaction is required and the attack complexity is low, an attacker with initial System access can reliably trigger this vulnerability to complete their attack chain.

Detection Methods for CVE-2025-20767

Indicators of Compromise

• Unexpected system crashes or reboots related to display driver operations
• Anomalous kernel panic logs referencing the display subsystem or MediaTek DDP (Display Data Path) components
• Evidence of privilege escalation attempts in system logs following display-related operations
• Suspicious processes running with elevated kernel privileges after display driver interactions

Detection Strategies

Kernel Log Monitoring: Monitor kernel logs (dmesg, logcat) for signs of memory corruption, particularly those associated with MediaTek display driver components. Look for out-of-bounds access warnings, buffer overflow detections, or unexpected page faults in the display subsystem.

Integrity Verification: Implement runtime integrity verification for critical kernel data structures that could be targeted by an out-of-bounds write attack. Hardware-backed integrity solutions can detect unauthorized modifications.

Behavioral Analysis: Deploy mobile threat defense solutions that can detect anomalous behavior patterns indicative of privilege escalation attempts, including unusual memory access patterns and unexpected system call sequences.

Monitoring Recommendations

Organizations should implement comprehensive mobile device monitoring that includes:

• Regular security log collection from Android devices, particularly those running on affected MediaTek chipsets
• Deployment of Mobile Threat Defense (MTD) solutions capable of detecting kernel-level exploitation attempts
• Periodic vulnerability scanning to identify devices running unpatched firmware versions
• Network-level monitoring for devices exhibiting suspicious behavior following potential exploitation

How to Mitigate CVE-2025-20767

Immediate Actions Required

• Apply the December 2025 MediaTek security patches (Patch ID: ALPS10196993) as soon as they become available from your device manufacturer
• Monitor device behavior for signs of compromise, especially on devices that may have been exposed to untrusted applications
• Restrict installation of applications from unknown sources to reduce the risk of attackers gaining initial System privilege
• Implement device management policies that enforce prompt security updates

Patch Information

MediaTek has released security patches addressing this vulnerability as documented in their December 2025 Product Security Bulletin. The fix is tracked under Patch ID ALPS10196993 and Issue ID MSV-4807.

Device manufacturers (OEMs) will need to integrate these patches into their Android builds and distribute updates to end users. The timeline for receiving patches varies by manufacturer and device model. Organizations should:

1. Contact device manufacturers for patch availability timelines
2. Prioritize updates for devices running affected MediaTek chipsets
3. Reference the official MediaTek security bulletin at: https://corp.mediatek.com/product-security-bulletin/December-2025

Workarounds

Since this vulnerability requires System-level privilege as a prerequisite for exploitation, the most effective workaround is to prevent attackers from achieving initial System access:

• Ensure all applications are sourced from trusted repositories (Google Play Store)
• Enable Google Play Protect for real-time application scanning
• Implement Mobile Device Management (MDM) policies to restrict device modifications
• Disable USB debugging and ADB access when not required for development
• Use strong device encryption and screen lock mechanisms

There are no direct workarounds to mitigate the vulnerability itself without applying the vendor patch, as the vulnerable code resides in the kernel-level display driver. Organizations should prioritize patch deployment for affected devices.