CVE-2026-20494: WiFi Information Disclosure Vulnerability

CVE-2026-20494 Overview

CVE-2026-20494 is an out-of-bounds read vulnerability in the MediaTek Wi-Fi component caused by a missing bounds check. An attacker with existing System-level privileges can trigger the flaw to read memory outside allocated buffers, resulting in local information disclosure. User interaction is not required for exploitation.

MediaTek tracks the fix under Patch ID ALPS10960006 with internal references BORA00155314, BORA00155001, and BORA00154907. The issue is catalogued as MSV-7570 in the MediaTek advisory system and classified under CWE-125.

Critical Impact
A local attacker with System privileges can read out-of-bounds memory in the Wi-Fi driver, exposing sensitive kernel or driver data that may aid further exploitation.

Affected Products

MediaTek chipsets containing the affected Wi-Fi driver component
Devices integrating firmware referenced by Patch ID ALPS10960006
Vendor devices tracking issue MSV-7570 in the MediaTek August 2026 bulletin

Discovery Timeline

2026-08-03 - CVE-2026-20494 published to NVD
2026-08-03 - Last updated in NVD database
August 2026 - Disclosed in the MediaTek Security Bulletin August 2026

Technical Details for CVE-2026-20494

Vulnerability Analysis

The vulnerability resides in the MediaTek Wi-Fi driver, where a code path fails to validate the size or offset of input data before performing a read operation. This missing bounds check allows the driver to read memory beyond the intended buffer boundary, exposing adjacent memory contents.

Exploitation requires the attacker to already hold System privileges on the device. As a result, the flaw does not provide initial access but functions as a post-compromise primitive. A privileged attacker can use the leak to bypass address space layout randomization (ASLR) or extract sensitive kernel structures.

The issue is classified as [CWE-125: Out-of-Bounds Read]. The confidentiality impact is high while integrity and availability are unaffected, consistent with a pure memory disclosure primitive.

Root Cause

The root cause is the absence of a length or index validation check before a memory read in the Wi-Fi driver. When attacker-influenced data drives the read offset or size, the driver dereferences memory outside the intended allocation. MediaTek's patch adds the missing bounds validation to constrain reads to allocated buffer ranges.

Attack Vector

The attack vector is local. The attacker must execute code with System privileges to reach the vulnerable Wi-Fi driver interface. No user interaction is required. Because privileged access is a prerequisite, exploitation typically occurs as a stage within a chained attack that combines an earlier privilege escalation with this information disclosure.

No verified public exploit code exists for CVE-2026-20494. See the MediaTek Security Bulletin August 2026 for vendor technical details.

Detection Methods for CVE-2026-20494

Indicators of Compromise

Unexpected processes running with System privileges interacting with Wi-Fi driver interfaces or ioctl endpoints
Anomalous kernel log entries referencing Wi-Fi driver reads, faults, or unusual buffer access patterns
Presence of unpatched firmware versions predating MediaTek Patch ID ALPS10960006

Detection Strategies

Monitor for privilege escalation activity that precedes access to Wi-Fi driver interfaces, since System privileges are a prerequisite for exploitation
Baseline legitimate Wi-Fi driver interactions and alert on unusual system-service processes issuing driver calls
Correlate mobile device management (MDM) telemetry with the MediaTek advisory to identify devices lacking the August 2026 patch

Monitoring Recommendations

Track kernel and Wi-Fi subsystem logs for repeated read errors or bounds-related warnings originating from the MediaTek driver
Inventory device firmware and chipset versions against the MediaTek bulletin to confirm patch status
Audit applications and services that hold System privileges on managed mobile devices to reduce the attacker population capable of triggering this flaw

How to Mitigate CVE-2026-20494

Immediate Actions Required

Apply the vendor firmware update containing MediaTek Patch ID ALPS10960006 referenced in the August 2026 security bulletin
Prioritize patching for devices where System-level applications or preinstalled services expose the vulnerable Wi-Fi interface
Restrict installation of untrusted System-privileged applications on affected mobile devices

Patch Information

MediaTek released a fix documented under Patch ID ALPS10960006 with change references BORA00155314, BORA00155001, and BORA00154907, tracked as issue MSV-7570. Device manufacturers must integrate the patched driver into their firmware and distribute the update through standard vendor over-the-air (OTA) channels. Consult the MediaTek Security Bulletin August 2026 for the authoritative advisory.

Workarounds

No vendor-supplied workaround exists; apply the firmware update once available from the device manufacturer
Enforce least-privilege policies to reduce the number of processes running with System privileges
Disable or restrict Wi-Fi features on high-risk devices until the patched firmware is deployed

bash

# Verify device firmware level against the MediaTek August 2026 bulletin
adb shell getprop ro.build.version.security_patch
adb shell getprop ro.vendor.build.security_patch