CVE-2026-20477 Memory corruption in MediaTek chipset

Medium 6.0 Published 3 Aug 2026 Updated 5 Aug 2026

A missing bounds check in MediaTek display drivers allows local privilege escalation for attackers with System privileges.

Exploited in the wild: Not known
Login needed: An administrator
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-20477?

CVE-2026-20477 is a medium-severity memory corruption vulnerability in MediaTek, Inc. MediaTek chipset, published on 3 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In display, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege if a malicious actor has already obtained the System privilege. User interaction is not needed for exploitation. Patch ID: ALPS11009963; Issue ID: MSV-7658.

Weakness: CWE-787

Which versions are affected by CVE-2026-20477?

It affects 10 products.

Products include Mediatek Mt6991 Firmware, Mediatek Mt6993 Firmware, Mediatek Mt8188 Firmware, Mediatek Mt8189 Firmware, Mediatek Mt8668 Firmware, Mediatek Mt8676 Firmware and 4 more.

How do I fix CVE-2026-20477?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-20477 being exploited?

There is no known exploitation of CVE-2026-20477 in the wild and no public exploit code.

Sources

Also known as A-518606098, ASB-A-518606098, GHSA-9jxv-qr96-p4v6, M-ALPS11009963.