CVE-2025-20797: Android Battery Privilege Escalation Flaw

CVE-2025-20797 Overview

CVE-2025-20797 is a local privilege escalation vulnerability affecting the battery driver component in MediaTek chipsets running Google Android. The vulnerability exists due to a missing bounds check in the battery driver, which allows an out-of-bounds write operation. An attacker who has already obtained System privilege on the device can exploit this flaw to further escalate privileges without requiring any user interaction.

Critical Impact

Local privilege escalation via out-of-bounds write in battery driver affecting numerous MediaTek chipsets across Android 14, 15, and 16 devices.

Affected Products

• Google Android 14.0, 15.0, and 16.0
• MediaTek MT6xxx series chipsets (MT6765, MT6768, MT6781, MT6833, MT6835, MT6853, MT6855, MT6877, MT6879, MT6893, MT6985, MT6989, MT6991)
• MediaTek MT8xxx series chipsets (MT8186, MT8188, MT8196, MT8367, MT8391, MT8676, MT8678, MT8696, MT8766, MT8768, MT8781, MT8786, MT8788e, MT8791t, MT8792, MT8793, MT8796, MT8873, MT8883, MT8893, MT2718)

Discovery Timeline

• January 6, 2026 - CVE-2025-20797 published to NVD
• January 8, 2026 - Last updated in NVD database

Technical Details for CVE-2025-20797

Vulnerability Analysis

This vulnerability resides in the battery driver component of MediaTek chipsets used in Android devices. The flaw is classified as CWE-787 (Out-of-bounds Write) and CWE-121 (Stack-based Buffer Overflow), indicating that the vulnerability occurs when the battery driver writes data beyond the allocated buffer boundaries.

The exploitation requires local access to the device and the attacker must have already obtained System-level privileges. Once exploited, the vulnerability enables further privilege escalation, potentially granting the attacker complete control over the affected device. The attack does not require any user interaction, making it particularly dangerous in scenarios where an attacker has already compromised the device through other means.

Root Cause

The root cause of CVE-2025-20797 is a missing bounds check in the battery driver code. When processing certain data, the driver fails to validate the size or index of input parameters before writing to memory. This oversight allows malicious input to write beyond the intended buffer boundaries, corrupting adjacent memory regions.

The specific issue is tracked internally by MediaTek as Patch ID: ALPS10315812 and Issue ID: MSV-5534. The vulnerability affects a wide range of MediaTek chipsets used in smartphones, tablets, and other Android-powered devices.

Attack Vector

The attack vector for this vulnerability is local, meaning an attacker must have some level of access to the target device. The exploitation scenario involves:

1. An attacker first gains System-level access to the Android device through another vulnerability or mechanism
2. The attacker then interacts with the battery driver, providing maliciously crafted input
3. Due to the missing bounds check, the driver writes data outside allocated memory boundaries
4. This out-of-bounds write corrupts critical data structures or function pointers
5. The attacker leverages the memory corruption to escalate privileges beyond System level

The vulnerability can be exploited without requiring any user interaction, which increases its severity in multi-stage attack scenarios.

Detection Methods for CVE-2025-20797

Indicators of Compromise

• Unusual system calls or ioctl operations targeting the battery driver interface
• Unexpected crashes or kernel panics related to the battery subsystem
• Evidence of privilege escalation attempts following battery driver interactions
• Anomalous memory access patterns in kernel logs associated with battery driver operations

Detection Strategies

• Monitor kernel logs for stack-based buffer overflow signatures or memory corruption indicators in battery-related drivers
• Implement runtime integrity checks for critical kernel data structures
• Deploy endpoint detection solutions capable of monitoring low-level driver interactions on Android devices
• Utilize SentinelOne's behavioral AI to detect privilege escalation patterns following system-level compromise

Monitoring Recommendations

• Enable verbose kernel logging for driver subsystems to capture potential exploitation attempts
• Monitor for unauthorized modifications to system partitions or privilege-related files
• Implement anomaly detection for processes that exhibit unusual privilege changes
• Track battery driver API calls for abnormal parameter values or call patterns

How to Mitigate CVE-2025-20797

Immediate Actions Required

• Apply the security patch from MediaTek's January 2026 Security Bulletin immediately
• Ensure all affected devices are updated to the latest Android security patch level
• Restrict physical and remote access to potentially affected devices until patching is complete
• Review device logs for any signs of exploitation attempts prior to patching

Patch Information

MediaTek has released a security patch addressing this vulnerability. The patch is identified as ALPS10315812 and is included in the MediaTek Security Bulletin January 2026. Device manufacturers should integrate this patch into their Android builds, and end users should apply the corresponding security updates when made available by their device vendors.

Organizations should coordinate with their device manufacturers to understand patch availability timelines for specific device models.

Workarounds

• Limit the installation of applications from untrusted sources to reduce initial compromise vectors
• Implement mobile device management (MDM) solutions to enforce security policies and restrict system-level access
• Isolate potentially vulnerable devices from sensitive network resources until patches are applied
• Enable SELinux enforcement to provide additional defense-in-depth against privilege escalation attempts

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

# Check for MediaTek chipset information
adb shell cat /proc/cpuinfo | grep Hardware