CVE-2025-20645 Overview
CVE-2025-20645 is an out-of-bounds write vulnerability in the MediaTek KeyInstall component affecting Google Android devices running on multiple MediaTek chipsets. The flaw stems from a missing bounds check that allows memory corruption during key installation operations. An attacker who has already obtained System privilege on the device can trigger the flaw to escalate to higher privilege levels. No user interaction is required for exploitation. MediaTek assigned Patch ID ALPS09475476 and Issue ID MSV-2599 to track the fix, published in the March 2025 MediaTek Product Security Bulletin.
Critical Impact
Local privilege escalation from System to kernel-level execution on Android devices running affected MediaTek chipsets, enabling full device compromise.
Affected Products
- Google Android 14.0 and 15.0 on MediaTek chipsets
- MediaTek chipsets: MT6765, MT6768, MT6833, MT6835, MT6853, MT6855, MT6879, MT6886, MT6893, MT6897
- MediaTek chipsets: MT6983, MT6985, MT6989, MT8796
Discovery Timeline
- 2025-03-03 - CVE-2025-20645 published to NVD
- March 2025 - MediaTek releases patch ALPS09475476 in Product Security Bulletin
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-20645
Vulnerability Analysis
The vulnerability resides in the KeyInstall component, a MediaTek proprietary service responsible for handling cryptographic key installation and management within the Trusted Execution Environment (TEE) interface layer. The component fails to validate input boundaries before writing data to a fixed-size buffer, allowing adjacent memory regions to be overwritten. This class of flaw is categorized under [CWE-787: Out-of-Bounds Write].
An attacker leveraging this weakness can corrupt kernel data structures to hijack control flow or manipulate privilege-related state. Because KeyInstall operates in a privileged context handling security-sensitive operations, successful exploitation grants attackers escalated access to cryptographic material and kernel resources.
Root Cause
The defect is a missing bounds check on user-controlled or caller-controlled input before performing a memory write operation within KeyInstall. Without size validation, the write operation extends beyond the intended buffer boundary. The absence of runtime length checks on structured data passed into the component creates the exploitable primitive.
Attack Vector
Exploitation requires local access and pre-existing System-level privileges on the target device. A malicious application or compromised system service with System UID can invoke the vulnerable KeyInstall interface with crafted parameters that trigger the out-of-bounds write. No user interaction is required. The vulnerability changes the scope by transitioning execution from System context into kernel or TEE-adjacent memory, breaking the Android security boundary between privileged userspace and the kernel.
Because KeyInstall handles cryptographic key material, secondary impacts include potential exposure or manipulation of stored keys used for disk encryption, attestation, and DRM operations. See the MediaTek Security Bulletin - March 2025 for vendor technical details.
Detection Methods for CVE-2025-20645
Indicators of Compromise
- Unexpected crashes or kernel panics referencing the KeyInstall driver or MediaTek TEE client in logcat or dmesg output
- Anomalous invocations of MediaTek key management IOCTLs originating from non-standard system processes
- Modification of protected kernel memory regions coinciding with key installation activity
Detection Strategies
- Monitor Android kernel logs for KeyInstall fault signatures, SELinux denials against MediaTek key nodes, and unexpected process behavior with System UID
- Deploy Mobile Threat Defense agents capable of identifying privilege escalation attempts and anomalous native library behavior on MediaTek devices
- Correlate device attestation failures with software installation events to identify post-exploitation tampering
Monitoring Recommendations
- Track MediaTek security patch level (ro.mediatek.version.security) across managed device fleets and flag devices missing the March 2025 patch
- Ingest mobile device telemetry into a centralized SIEM to identify clusters of System-privileged process crashes across the fleet
- Enable Google Play Protect and mobile threat identification services to detect malicious applications attempting local privilege escalation
How to Mitigate CVE-2025-20645
Immediate Actions Required
- Apply the March 2025 Android security patch level or later on all affected MediaTek-based devices
- Inventory managed devices by chipset identifier and prioritize patch deployment for the listed MediaTek SoCs
- Restrict installation of untrusted applications and enforce Mobile Device Management (MDM) policies that block sideloading
Patch Information
MediaTek addressed the vulnerability with Patch ID ALPS09475476 (Issue ID MSV-2599), delivered through OEM firmware updates aligned with the March 2025 Android security bulletin cycle. Device manufacturers integrate the patch into their monthly security maintenance releases. Users should install the latest security update available from their device vendor. Details are published in the MediaTek Product Security Bulletin - March 2025.
Workarounds
- No official workaround exists; patching is the only complete remediation
- Reduce attack surface by removing unnecessary System-privileged applications and vendor bloatware where possible
- Enforce hardware attestation and block enrollment of devices below the March 2025 patch level in enterprise access policies
# Verify Android security patch level on a connected device
adb shell getprop ro.build.version.security_patch
# Check MediaTek-specific security version if exposed
adb shell getprop | grep -i security
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
