CVE-2025-20795: Google Android Privilege Escalation Flaw

CVE-2025-20795 Overview

CVE-2025-20795 is an out-of-bounds write vulnerability in the MediaTek KeyInstall component affecting numerous MediaTek chipsets used in Android devices. The vulnerability exists due to a missing bounds check in the KeyInstall module, which could allow a local attacker who has already obtained System privileges to further escalate their access. This vulnerability does not require user interaction for exploitation, making it particularly concerning for devices that may already be compromised.

Critical Impact

Local privilege escalation vulnerability in MediaTek KeyInstall component affects over 50 MediaTek chipsets across Android 13.0 through 16.0, enabling attackers with System privileges to escalate access without user interaction.

Affected Products

• Google Android 13.0, 14.0, 15.0, and 16.0
• MediaTek MT6xxx series chipsets (including MT6580, MT6739, MT6761, MT6765, MT6768, MT6779, MT6781, MT6785, MT6789, MT6833, MT6835, MT6853, MT6855, MT6873, MT6877, MT6878, MT6879, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899, MT6983, MT6985, MT6989, MT6991)
• MediaTek MT8xxx series chipsets (including MT8186, MT8188, MT8195, MT8196, MT8370, MT8390, MT8391, MT8395, MT8676, MT8678, MT8696, MT8755, MT8766, MT8768, MT8781, MT8786, MT8788e, MT8791t, MT8792, MT8793, MT8796, MT8873, MT8883, MT8893)
• MediaTek MT2718 chipset

Discovery Timeline

• 2026-01-06 - CVE-2025-20795 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-20795

Vulnerability Analysis

This vulnerability (tracked as Patch ID: ALPS10276761 and Issue ID: MSV-5141) is classified as CWE-787 (Out-of-Bounds Write). The KeyInstall component is responsible for secure key installation and management on MediaTek-powered Android devices. When processing certain operations, the component fails to properly validate the boundaries of memory write operations, allowing an attacker to write data beyond the intended buffer limits.

The local attack vector means an attacker must have local access to the device to exploit this vulnerability. However, the prerequisite of already having System privileges limits the immediate impact but creates a pathway for deeper system compromise, potentially affecting the secure execution environment or other protected system components.

Root Cause

The root cause of CVE-2025-20795 is a missing bounds check in the KeyInstall component. When the component handles key installation requests, it fails to validate the size of input data against the allocated buffer size before performing write operations. This oversight allows an attacker to supply crafted input that causes data to be written beyond the intended memory boundaries, potentially corrupting adjacent memory structures or overwriting critical data.

Attack Vector

An attacker exploiting this vulnerability would need to:

1. First obtain System-level privileges on the target Android device through another vulnerability or attack method
2. Interact with the KeyInstall component by supplying specially crafted input data
3. Trigger the out-of-bounds write condition to corrupt memory and escalate privileges further

The exploitation does not require any user interaction, meaning a compromised application with System privileges could silently exploit this vulnerability. The impact includes high confidentiality, integrity, and availability consequences, potentially allowing access to protected system resources, modification of critical system data, or causing system instability.

Detection Methods for CVE-2025-20795

Indicators of Compromise

• Unusual system calls or interactions with the KeyInstall component from processes that typically do not require key management functionality
• Anomalous memory allocation patterns or crashes in system services related to key management
• Evidence of privilege escalation attempts in system logs, particularly involving TEE (Trusted Execution Environment) operations
• Unexpected modifications to system partitions or secure storage areas

Detection Strategies

• Implement behavioral monitoring to detect abnormal process privilege transitions on Android devices
• Deploy endpoint detection solutions capable of monitoring low-level system component interactions
• Review Android system logs for KeyInstall-related errors or unusual activity patterns
• Monitor for applications requesting or utilizing System-level permissions without legitimate business need

Monitoring Recommendations

• Enable verbose logging for security-sensitive system components where available
• Deploy mobile threat defense solutions with capability to detect privilege escalation attempts
• Implement device attestation to verify system integrity on managed Android devices
• Establish baseline behavior for critical system components to detect anomalous activity

How to Mitigate CVE-2025-20795

Immediate Actions Required

• Apply the January 2026 security updates from MediaTek and Google as soon as they become available for your device
• Review and restrict applications that have been granted elevated system permissions
• Implement mobile device management (MDM) policies to enforce timely security updates
• Monitor devices for signs of compromise, particularly those in high-risk environments

Patch Information

MediaTek has released a security patch addressing this vulnerability, tracked as Patch ID: ALPS10276761. The fix is documented in the MediaTek Security Bulletin January 2026. Device manufacturers and carriers will incorporate this patch into their Android security updates. Users should ensure their devices are updated to the latest available security patch level that includes this fix.

Workarounds

• Limit installation of applications from untrusted sources to reduce the risk of initial compromise
• Implement application sandboxing and restrict system-level permissions for non-essential applications
• Use Android Enterprise work profiles to isolate sensitive data and applications
• Consider enterprise-managed devices with strict security policies for high-security environments
• Regularly audit installed applications and revoke unnecessary permissions

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

# Check device software version
adb shell getprop ro.build.display.id

# List packages with system-level permissions for audit
adb shell pm list packages -f | grep system