CVE-2026-20489 Overview
CVE-2026-20489 is an integer overflow vulnerability in the MediaTek display component that enables local information disclosure. An attacker with existing System privileges can trigger the overflow to read out-of-bounds memory. Exploitation requires no user interaction. MediaTek tracks the fix under Patch ID ALPS11004274 and Issue ID MSV-7749. The weakness maps to [CWE-125] (Out-of-bounds Read) and stems from arithmetic that wraps during size or offset computation in the display path.
Critical Impact
A local attacker holding System privilege can read sensitive memory from the display component without user interaction, exposing data that should remain isolated.
Affected Products
- MediaTek chipsets containing the vulnerable display component (see the MediaTek Security Bulletin August 2026)
- Android devices integrating affected MediaTek firmware
- Device firmware images shipped without Patch ID ALPS11004274
Discovery Timeline
- 2026-08-03 - CVE-2026-20489 published to NVD
- 2026-08-03 - MediaTek publishes the August 2026 Product Security Bulletin
- 2026-08-03 - Last updated in NVD database
Technical Details for CVE-2026-20489
Vulnerability Analysis
The vulnerability resides in the MediaTek display component. Arithmetic used during buffer sizing or offset calculation overflows the fixed-width integer type, producing a value smaller than intended. Downstream code then trusts the wrapped value when accessing a buffer, resulting in an out-of-bounds read classified under [CWE-125].
Because the read occurs inside a privileged display path, the leaked bytes may include memory contents the caller could not otherwise reach. The attack vector is local, and exploitation requires the caller to already hold System-level privileges on the device. No user interaction is required.
The primary consequence is confidentiality loss. The vulnerability does not directly grant code execution, integrity impact, or denial of service based on the published information.
Root Cause
The root cause is unchecked integer arithmetic in the display component. Input values are combined without validating against the maximum representable size of the destination integer. When the computed size wraps, the subsequent memory access reads past the intended boundary and returns residual data to the caller.
Attack Vector
An attacker first obtains System privilege through a separate flaw or a compromised system-level process. From that context, the attacker issues a crafted request to the display component with parameters chosen to trigger the overflow. The component returns data from adjacent memory, which the attacker then exfiltrates. The vulnerability is not remotely reachable and cannot be triggered by unprivileged applications directly.
No public proof-of-concept or exploit code is available. See the MediaTek Security Bulletin August 2026 for vendor-supplied technical details.
Detection Methods for CVE-2026-20489
Indicators of Compromise
- Unpatched MediaTek firmware builds that do not include Patch ID ALPS11004274
- System-level processes issuing unusual or malformed requests to the display component
- Anomalous memory read patterns originating from display driver interfaces
Detection Strategies
- Inventory MediaTek-based device firmware and compare build strings against the patched versions listed in the August 2026 MediaTek bulletin.
- Monitor for privilege escalation chains that precede display component activity, since System privilege is a prerequisite.
- Correlate crash or kernel log entries from the display driver with unexpected parameter values.
Monitoring Recommendations
- Collect kernel and driver logs from managed Android endpoints into a centralized data lake for retrospective analysis.
- Alert on new or unsigned system-level processes interacting with display driver IOCTLs.
- Track patch level attestation from managed devices and flag builds missing ALPS11004274.
How to Mitigate CVE-2026-20489
Immediate Actions Required
- Apply the vendor firmware update containing Patch ID ALPS11004274 as soon as it is available from the device OEM.
- Restrict which components run with System privilege and audit existing System-level code paths that call into the display component.
- Enforce mobile device management policies that require the August 2026 or later Android security patch level on MediaTek devices.
Patch Information
MediaTek addressed the issue with Patch ID ALPS11004274, tracked internally as Issue ID MSV-7749. The fix is documented in the MediaTek Security Bulletin August 2026. Device OEMs must integrate the patch into their firmware releases before end users receive protection.
Workarounds
- No vendor-supplied workaround is published; reduce the number of processes holding System privilege to limit exploit prerequisites.
- Block installation of unverified system-level applications through enterprise mobile management.
- Where feasible, replace end-of-support devices that will not receive the August 2026 MediaTek patch.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
