CVE-2026-20501: MediaTek Chipset Heap Buffer Overflow Vulnerability

Executive Summary

A high-severity vulnerability, CVE-2026-20501, with a CVSS score of 8.4, has been identified in various MediaTek chipsets. This vulnerability could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not required for exploitation. This threat briefing provides an overview of the vulnerability, its technical analysis, exploitation scenario, impact assessment, and recommended actions.

Technical Analysis

The vulnerability is classified as a heap buffer overflow in the vdec component of MediaTek chipsets. The attack vector is local, meaning an attacker must have access to the device. The root cause of this vulnerability is a lack of proper input validation, allowing an attacker to write out of bounds, potentially leading to privilege escalation.

How It Gets Exploited

An attacker with local access to a vulnerable MediaTek chipset can trigger this vulnerability. The exploitation scenario involves the attacker sending a crafted payload to the vulnerable component, which fails to validate the input length, causing a heap buffer overflow. This overflow can overwrite adjacent memory, potentially allowing the attacker to execute arbitrary code and escalate privileges.

Impact Assessment

Multiple MediaTek chipset versions are affected, including but not limited to MT2718, MT6580, MT6739, MT6761, MT6765, and many others. An attacker exploiting this vulnerability could achieve local escalation of privilege, potentially leading to arbitrary code execution, data tampering, or denial of service. The CVSS score of 8.4 indicates a high severity level.

Recommended Actions

To mitigate this vulnerability, it is recommended to update affected MediaTek chipsets to a patched version. Specifically, apply Patch ID: ALPS11262030 as mentioned in the vendor's security bulletin. For detailed patch information and affected products, refer to MediaTek's product security bulletin for September 2026.

Sources

- National Vulnerability Database (NVD) - MediaTek Product Security Bulletin for September 2026