CVE-2026-20509

Published Sep 7, 2026 CVSS 3.1 · 6.7 Medium EPSS < 1% KEV · Not listed

Description

In Power HAL, 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: ALPS11165543; Issue ID: MSV-9011.

Analysis

Technical impact

An out‑of‑bounds write in the Power HAL module of MediaTek chipsets occurs because a bounds check is omitted. This flaw, classified as CWE-121, could allow a locally running entity that already has System privilege to overwrite memory beyond its intended bounds, potentially corrupting critical data structures or code paths. The result is an escalation of privileges from System level to higher or equivalent authority within the device. User interaction is not required for exploitation.

Affected Systems

MediaTek, Inc. chipsets are affected. The vulnerability exists in the Power HAL component of these hardware platforms. No specific affected firmware or hardware versions are disclosed.

Risk and Exploitability

The CVSS score is 6.7, the EPSS score is less than 1%, and the issue is not listed in the CISA KEV catalog. The flaw can be triggered locally by any process running with System permissions. Attackers with such access could manipulate memory without needing to interact with a user interface. The potential impact, if exploited successfully, would be severe due to the high privilege level involved.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

MediaTek, Inc.

MediaTek chipset

unaffected

Version	Status	Constraints
`MT2718`	affected	—
`MT6739`	affected	—
`MT6761`	affected	—
`MT6765`	affected	—
`MT6768`	affected	—
`MT6769`	affected	—
`MT6781`	affected	—
`MT6789`	affected	—
`MT6833`	affected	—
`MT6835`	affected	—
`MT6853`	affected	—
`MT6855`	affected	—
`MT6858`	affected	—
`MT6877`	affected	—
`MT6878`	affected	—
`MT6879`	affected	—
`MT6881`	affected	—
`MT6883`	affected	—
`MT6885`	affected	—
`MT6886`	affected	—
`MT6889`	affected	—
`MT6893`	affected	—
`MT6895`	affected	—
`MT6897`	affected	—
`MT6899`	affected	—
`MT6983`	affected	—
`MT6985`	affected	—
`MT6989`	affected	—
`MT6991`	affected	—
`MT6993`	affected	—
`MT8171`	affected	—
`MT8186`	affected	—
`MT8188`	affected	—
`MT8189`	affected	—
`MT8196`	affected	—
`MT8668`	affected	—
`MT8676`	affected	—
`MT8678`	affected	—
`MT8696`	affected	—
`MT8793`	affected	—

No data.

Vendor Product Versions

Mediatek, Inc.

Mediatek Chipset

Version	Status	Scheme	Platform
`MT2718`	affected	generic	—
`MT6739`	affected	generic	—
`MT6761`	affected	generic	—
`MT6765`	affected	generic	—
`MT6768`	affected	generic	—
`MT6769`	affected	generic	—
`MT6781`	affected	generic	—
`MT6789`	affected	generic	—
`MT6833`	affected	generic	—
`MT6835`	affected	generic	—
`MT6853`	affected	generic	—
`MT6855`	affected	generic	—
`MT6858`	affected	generic	—
`MT6877`	affected	generic	—
`MT6878`	affected	generic	—
`MT6879`	affected	generic	—
`MT6881`	affected	generic	—
`MT6883`	affected	generic	—
`MT6885`	affected	generic	—
`MT6886`	affected	generic	—
`MT6889`	affected	generic	—
`MT6893`	affected	generic	—
`MT6895`	affected	generic	—
`MT6897`	affected	generic	—
`MT6899`	affected	generic	—
`MT6983`	affected	generic	—
`MT6985`	affected	generic	—
`MT6989`	affected	generic	—
`MT6991`	affected	generic	—
`MT6993`	affected	generic	—
`MT8171`	affected	generic	—
`MT8186`	affected	generic	—
`MT8188`	affected	generic	—
`MT8189`	affected	generic	—
`MT8196`	affected	generic	—
`MT8668`	affected	generic	—
`MT8676`	affected	generic	—
`MT8678`	affected	generic	—
`MT8696`	affected	generic	—
`MT8793`	affected	generic	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the latest firmware patch (ALPS11165543) that fixes the bounds check in the Power HAL module.
Ensure the device firmware is updated to the patched version before any further deployment.
Verify that all processes on the device run with least privilege; consider disabling unnecessary System‑level services to reduce the attack surface.

Generated by OpenCVE AI on September 7, 2026 at 16:06 UTC.

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required High

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.168% probability within 30 days)

Exploitation none

Automatable no

Technical Impact total

References

Link	Providers
https://www.mediatek.com/product-security-bulletin/September-2026

History

Sep 7, 2026 4:30 PM Title updated View changes

Type	Values Removed	Values Added
Title	Potential Out‑of‑Bounds Write in MediaTek Power HAL Leading to Local Privilege Escalation

Sep 7, 2026 11:30 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 6.7, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'}` ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Sep 7, 2026 4:00 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Mediatek, Inc. Mediatek, Inc. mediatek Chipset
Vendors & Products		Mediatek, Inc. Mediatek, Inc. mediatek Chipset

Sep 7, 2026 3:45 AM Title updated View changes

Type	Values Removed	Values Added
Title		Potential Out‑of‑Bounds Write in MediaTek Power HAL Leading to Local Privilege Escalation

Sep 7, 2026 2:00 AM Description updated. Weaknesses updated. Added references View changes

Type	Values Removed	Values Added
Description		In Power HAL, 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: ALPS11165543; Issue ID: MSV-9011.
Weaknesses		CWE-121
References		https://www.mediatek.com/product-security-bulletin/September-2026