CVE-2025-20668: Google Android Privilege Escalation Flaw

CVE-2025-20668 Overview

CVE-2025-20668 is an out-of-bounds write vulnerability in the MediaTek System Control Processor (scp) component. The flaw stems from a missing bounds check and affects Google Android devices running on multiple MediaTek chipsets. An attacker with System-level privileges on the device can trigger the condition to escalate to higher privileges. Exploitation requires no user interaction and no additional execution privileges beyond the already-held System context. MediaTek addressed the issue in its May 2025 Product Security Bulletin under Patch ID ALPS09625562 and Issue ID MSV-3027. The vulnerability is tracked under CWE-787 (Out-of-bounds Write).

Critical Impact
A local attacker holding Android System privileges can trigger an out-of-bounds write in the MediaTek scp firmware path to achieve local privilege escalation, potentially reaching kernel or SCP-level execution on affected chipsets.

Affected Products

Google Android 14.0 and Android 15.0 running on affected MediaTek platforms
MediaTek chipsets: MT6878, MT6897, MT6899, MT6989, MT6991
MediaTek automotive/embedded chipsets: MT8775, MT8796

Discovery Timeline

2025-05-05 - CVE-2025-20668 published to the National Vulnerability Database
May 2025 - MediaTek releases security patch in the Product Security Bulletin (Patch ID ALPS09625562)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-20668

Vulnerability Analysis

The vulnerability resides in the MediaTek System Control Processor (scp) subsystem, which is a coprocessor used across MediaTek SoCs for sensor hub, audio DSP coordination, and low-power tasks. The scp driver path processes input data without validating buffer boundaries. Because the missing check occurs before a write operation, an attacker can direct data past the intended buffer region and corrupt adjacent memory. Successful exploitation compromises the confidentiality, integrity, and availability of the affected device. The attack is local in nature; the actor must already execute code at the Android System privilege level before triggering the flaw. From System context, the write primitive can be used to pivot into kernel or SCP execution, which sits outside standard Android sandbox boundaries.

Root Cause

The root cause is a missing bounds check ([CWE-787]) in an scp code path that copies attacker-controllable data into a fixed-size destination buffer. Without validation of length or offset parameters, the write operation extends beyond the allocated region. MediaTek's patch ALPS09625562 adds the missing validation logic to reject oversized or malformed inputs before the write occurs.

Attack Vector

Exploitation requires local access with the Android System privilege already established, typically through a prior compromise of a privileged Android component or a chained vulnerability. The attacker issues crafted requests to the vulnerable scp interface, supplying parameters that bypass the absent length check. The resulting out-of-bounds write corrupts memory structures that can be shaped to gain arbitrary code execution or elevate privileges beyond the Android System user. No phishing, user interaction, or network access is required.

Verified proof-of-concept code has not been publicly released. Refer to the MediaTek Product Security Bulletin – May 2025 for advisory details.

Detection Methods for CVE-2025-20668

Indicators of Compromise

Unexpected crashes or reboots of the scp firmware or associated Android services on affected MediaTek chipsets
Kernel logs (dmesg, logcat) containing SCP fault messages, memory access violations, or watchdog resets tied to the SCP subsystem
Presence of unauthorized processes or binaries running with elevated privileges following a suspected exploitation attempt
Devices running Android 14 or 15 on affected chipsets that have not applied the May 2025 MediaTek patch level

Detection Strategies

Inventory mobile fleet devices and identify handsets or embedded units running the affected MediaTek chipsets listed above
Monitor Android security patch levels via mobile device management (MDM) reporting and flag devices missing the May 2025 or later MediaTek patch
Correlate crash telemetry from mobile endpoints against the SCP subsystem to identify anomalous fault patterns

Monitoring Recommendations

Enable centralized log collection from managed Android endpoints and forward SCP, kernel, and system service logs to a SIEM for pattern analysis
Alert on privilege escalation indicators such as unexpected root or system-level process creation on managed devices
Track OEM firmware update compliance and generate reports on devices lagging behind the vendor patch baseline

How to Mitigate CVE-2025-20668

Immediate Actions Required

Apply the Android security update that incorporates MediaTek Patch ID ALPS09625562 from the May 2025 bulletin as soon as the OEM makes it available
Identify devices in the fleet running the affected MediaTek chipsets and prioritize patch deployment through your MDM platform
Restrict installation of untrusted applications and audit existing apps that hold elevated Android permissions to reduce the pool of processes able to reach System privilege

Patch Information

MediaTek published the fix in the MediaTek Product Security Bulletin – May 2025 under Patch ID ALPS09625562 and Issue ID MSV-3027. Device manufacturers integrate the patch into their Android security patch level updates. Contact the device OEM (Google, Samsung, Xiaomi, Oppo, Vivo, and others using the listed chipsets) for update availability specific to each handset model.

Workarounds

No official vendor-supplied workaround exists; patching is the only supported remediation
Reduce exposure by limiting sideloaded applications and disabling debugging interfaces (ADB) on production devices
Enforce mobile application vetting policies to reduce the likelihood of an attacker gaining the prerequisite System privilege
For embedded and automotive deployments using MT8775 or MT8796, coordinate with the platform integrator to schedule firmware updates through the supported OTA channel