CVE-2025-20764: Google Android Privilege Escalation Flaw

CVE-2025-20764 Overview

CVE-2025-20764 is a high-severity out-of-bounds write vulnerability affecting the System Management Interface (SMI) component in MediaTek chipsets running Google Android. The vulnerability exists due to a missing bounds check, which could allow an attacker who has already obtained System-level privileges to escalate their privileges further. Notably, this vulnerability requires no user interaction to exploit, making it particularly dangerous in targeted attack scenarios.

Critical Impact

Local privilege escalation via out-of-bounds write in MediaTek SMI component affecting Android devices with 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 MT6739, MT6761, MT6765, MT6768, MT6781, MT6789
• MediaTek MT6833, MT6835, MT6853, MT6855, MT6877, MT6878
• MediaTek MT6879, MT6883, MT6885, MT6886, MT6889, MT6893
• MediaTek MT6895, MT6897, MT6899, MT6983, MT6985, MT6989, MT6991
• MediaTek MT8196, MT8676, MT8678, MT8792, MT8793, MT8796, MT8873, MT8893

Discovery Timeline

• 2025-12-02 - CVE-2025-20764 published to NVD
• 2025-12-03 - Last updated in NVD database

Technical Details for CVE-2025-20764

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-Bounds Write) and affects the SMI (System Management Interface) component within MediaTek chipset firmware. The CVSS 3.1 score of 7.8 (HIGH) reflects the significant impact of successful exploitation, with the attack vector being local (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

The vulnerability enables complete compromise of confidentiality, integrity, and availability on affected devices. While the attack complexity is low and no user interaction is required, the attacker must first obtain local access with low privileges. However, the critical aspect is that an attacker with System privilege can leverage this vulnerability to achieve further privilege escalation.

The EPSS (Exploit Prediction Scoring System) indicates a 0.005% probability of exploitation in the wild, placing this vulnerability in the 21.1st percentile of all scored vulnerabilities as of 2025-12-16.

Root Cause

The root cause of CVE-2025-20764 is a missing bounds check in the SMI component. When processing certain input data, the SMI handler fails to validate the size or offset of write operations, allowing memory writes beyond the allocated buffer boundaries. This type of vulnerability typically occurs when:

1. Array indices or buffer offsets are not properly validated against maximum bounds
2. Size calculations do not account for edge cases or malformed input
3. Trust assumptions are made about data received from lower-privilege contexts

The vulnerability has been assigned Patch ID ALPS10259774 and Issue ID MSV-5029 by MediaTek for tracking purposes.

Attack Vector

The attack vector for CVE-2025-20764 is local, meaning an attacker must have existing access to the device. The exploitation path involves:

1. The attacker first gains local access to the Android device with low-privilege credentials
2. Through another vulnerability or social engineering, the attacker escalates to System privilege
3. The attacker then triggers the out-of-bounds write in the SMI component by providing specially crafted input that bypasses the missing bounds check
4. The out-of-bounds write allows modification of critical memory structures, enabling kernel-level or root privilege escalation

The vulnerability in the SMI component is particularly concerning because the System Management Interface operates at a hardware abstraction layer, potentially providing pathways to compromise trusted execution environments or bypass security boundaries enforced by the Android operating system.

Detection Methods for CVE-2025-20764

Indicators of Compromise

• Unexpected crashes or reboots in Android devices with MediaTek chipsets
• Unusual SMI-related errors in kernel logs or system crash dumps
• Signs of privilege escalation from System to root or kernel context
• Anomalous memory access patterns in kernel memory regions
• Unauthorized modifications to system partitions or security-critical files

Detection Strategies

Organizations should implement multiple layers of detection to identify potential exploitation attempts:

Kernel Log Monitoring: Monitor for SMI-related errors, memory corruption signatures, or unexpected privilege transitions in kernel logs. Look for patterns indicating out-of-bounds memory access or abnormal SMI handler behavior.

Behavioral Analysis: Deploy endpoint detection and response (EDR) solutions capable of detecting anomalous process behavior, including unexpected privilege escalations from System-level processes.

Memory Integrity Monitoring: Implement kernel-level memory integrity checking where supported to detect unauthorized modifications to protected memory regions.

SentinelOne Singularity Platform: SentinelOne's behavioral AI engine can detect exploitation attempts by monitoring for suspicious system-level activities and privilege escalation patterns characteristic of memory corruption exploits.

Monitoring Recommendations

Establish baseline behavior for devices with MediaTek chipsets and configure alerts for:

• Kernel panic events or unexpected system crashes
• Privilege escalation events from System to higher privilege levels
• Unusual system call patterns from SMI-related processes
• Changes to critical system files or security configurations without authorized updates

How to Mitigate CVE-2025-20764

Immediate Actions Required

• Apply the latest security patches from MediaTek (Patch ID: ALPS10259774) as soon as they are available through OEM updates
• Ensure Android devices are updated to the latest available firmware version from the device manufacturer
• Restrict physical access to affected devices and implement strong device authentication
• Monitor for and remediate any existing compromise of System-level privileges on affected devices
• Deploy mobile device management (MDM) solutions to enforce security policies and ensure timely patch deployment

Patch Information

MediaTek has addressed this vulnerability in their December 2025 Product Security Bulletin. The fix is identified by Patch ID ALPS10259774 and Issue ID MSV-5029. Device manufacturers integrating MediaTek chipsets should incorporate this patch into their firmware updates.

Affected Android versions include 14.0, 15.0, and 16.0 running on the extensive list of MediaTek chipsets identified in this advisory. End users should:

1. Check for security updates from their device manufacturer
2. Apply all available system updates promptly
3. Contact their device manufacturer for patch availability timelines

For detailed patch information, refer to the MediaTek Product Security Bulletin: https://corp.mediatek.com/product-security-bulletin/December-2025

Workarounds

There are no official workarounds available for CVE-2025-20764 due to the nature of the vulnerability residing in low-level firmware components. However, organizations can implement defense-in-depth measures:

• Limit installation of applications from untrusted sources to reduce the risk of attackers gaining initial access
• Enable and enforce Google Play Protect for enhanced malware detection
• Implement application sandboxing and containerization for sensitive applications
• Use mobile threat defense solutions to detect malicious applications attempting to exploit system vulnerabilities
• Segment networks to limit lateral movement if a device is compromised
• Consider device replacement for critical use cases if timely patches are unavailable from the device manufacturer