CVE-2025-20643: Google Android Information Disclosure Flaw

CVE-2025-20643 Overview

CVE-2025-20643 is an out-of-bounds read vulnerability in the Download Agent (DA) component of MediaTek chipsets running on Google Android devices. The vulnerability exists due to a missing bounds check, which could allow an attacker with physical access to the device and elevated System privileges to read memory outside the intended boundaries, potentially leading to local information disclosure.

Critical Impact

An attacker with physical device access and System-level privileges can exploit this vulnerability to leak sensitive information from device memory, potentially exposing cryptographic keys, authentication tokens, or other confidential data stored in adjacent memory regions.

Affected Products

• Google Android versions 12.0, 13.0, 14.0, and 15.0
• MediaTek MT67xx series chipsets (MT6739, MT6761, MT6765, MT6768, MT6771, MT6779, MT6781, MT6785, MT6833, MT6853, MT6873, MT6877, MT6885, MT6893)
• MediaTek MT81xx/MT82xx/MT83xx/MT87xx/MT88xx series chipsets (including MT8167, MT8175, MT8185, MT8195, MT8321, MT8362a, MT8365, MT8385, MT8395, MT8666, MT8667, MT8673, MT8675, MT8678, MT8765, MT8766, MT8768, MT8771, MT8775, MT8781, MT8786, MT8788, MT8789, MT8791T, MT8795T, MT8797, MT8798, MT8893)

Discovery Timeline

• February 3, 2025 - CVE-2025-20643 published to NVD
• February 4, 2025 - Last updated in NVD database

Technical Details for CVE-2025-20643

Vulnerability Analysis

This vulnerability is classified as an out-of-bounds read (CWE-125) with improper isolation of shared resources (CWE-1295). The flaw resides in MediaTek's Download Agent (DA), a low-level component used during device firmware operations such as flashing and recovery procedures. The DA operates with elevated privileges during boot and maintenance operations, making it a sensitive attack surface.

The exploitation scenario requires physical access to the device, high privilege levels (System privilege must already be obtained), and user interaction. While these prerequisites limit the attack surface significantly, the vulnerability could be chained with other exploits in sophisticated attacks targeting high-value devices or in forensic extraction scenarios.

Root Cause

The root cause of CVE-2025-20643 is a missing bounds check in the Download Agent component. When processing certain input data, the DA fails to validate that array indices or buffer offsets fall within expected boundaries before performing read operations. This lack of validation allows read operations to access memory locations beyond the intended buffer, potentially exposing sensitive information stored in adjacent memory regions.

Attack Vector

The attack vector for this vulnerability requires physical access to the target device. An attacker must:

1. Gain physical access to a vulnerable Android device with a MediaTek chipset
2. Already possess or obtain System-level privileges on the device
3. Interact with the Download Agent component during device maintenance operations
4. Craft malicious input that triggers the out-of-bounds read condition
5. Extract leaked memory contents that may contain sensitive data

The physical access requirement and the need for prior System privilege significantly limit practical exploitation scenarios but make this vulnerability relevant in targeted attacks, device theft scenarios, or forensic analysis contexts.

Detection Methods for CVE-2025-20643

Indicators of Compromise

• Unusual activity or unexpected processes accessing the Download Agent during device boot or maintenance modes
• Unauthorized physical connections to the device via USB or other debug interfaces
• Evidence of firmware modification or unauthorized flashing attempts
• Anomalous memory access patterns in system logs if available

Detection Strategies

• Monitor for unauthorized physical access to devices, especially in enterprise or high-security environments
• Implement device management policies that alert on unexpected device state changes or boot mode entries
• Deploy endpoint detection solutions capable of monitoring low-level firmware and bootloader activities
• Review device logs for signs of DA component access outside normal maintenance windows

Monitoring Recommendations

• Enable comprehensive logging on managed Android devices where supported
• Implement physical security controls for sensitive devices containing MediaTek chipsets
• Configure mobile device management (MDM) solutions to track device integrity and detect tampering
• Establish baseline behavior for device maintenance operations to identify anomalous patterns

How to Mitigate CVE-2025-20643

Immediate Actions Required

• Apply the latest security patches from your device manufacturer as they become available
• Ensure devices are running the most current firmware versions that include MediaTek's fix
• Implement strong physical security controls for devices in sensitive environments
• Review and restrict access to debug interfaces and maintenance modes on managed devices

Patch Information

MediaTek has addressed this vulnerability with Patch ID ALPS09291146 (Issue ID: MSV-2056). Organizations should consult the MediaTek February 2025 Security Bulletin for detailed patch information. Device manufacturers will incorporate this fix into their Android security updates, which should be applied as soon as available for affected device models.

Workarounds

• Restrict physical access to vulnerable devices until patches can be applied
• Disable or restrict access to USB debugging and other maintenance interfaces when not actively needed
• Implement device encryption to reduce the impact of potential information disclosure
• Use device management solutions to enforce security policies and monitor for unauthorized access attempts

# Android device security hardening example
# Disable USB debugging when not in use
adb shell settings put global adb_enabled 0

# Verify device encryption status
adb shell getprop ro.crypto.state
# Should return "encrypted" for properly secured devices