CVE-2026-20452 Overview
CVE-2026-20452 is a heap buffer overflow vulnerability in the MediaTek WLAN access point (AP) driver. The flaw enables memory corruption that can lead to remote code execution from an adjacent network position. Exploitation requires low-level user privileges but no user interaction, making it a viable vector for attackers within wireless range of an affected device. MediaTek tracks the issue as Patch ID WCNCR00480138 and Issue ID MSV-6295, and addressed it in the June 2026 Product Security Bulletin. The vulnerability affects multiple MediaTek Wi-Fi chipsets widely deployed in consumer and enterprise networking equipment.
Critical Impact
An adjacent attacker with low privileges can trigger heap corruption in the WLAN AP driver to achieve code execution on affected MediaTek-based wireless infrastructure without user interaction.
Affected Products
- MediaTek MT6890, MT7615, MT7915, MT7916 chipsets and firmware
- MediaTek MT7981, MT7986, MT7990 chipsets and firmware
- MediaTek MT7992, MT7993 chipsets and firmware
Discovery Timeline
- 2026-06-01 - CVE-2026-20452 published to NVD
- 2026-06-01 - MediaTek publishes June 2026 Product Security Bulletin with patch WCNCR00480138
- 2026-06-01 - Last updated in NVD database
Technical Details for CVE-2026-20452
Vulnerability Analysis
The vulnerability resides in the WLAN AP driver responsible for handling wireless client traffic on MediaTek Wi-Fi silicon. A heap buffer overflow [CWE-122] occurs when the driver writes beyond the bounds of a dynamically allocated buffer during processing of wireless frames or management data. Because the driver executes within a privileged kernel or firmware context, successful exploitation grants the attacker the ability to corrupt adjacent heap structures and influence control flow.
The attack vector is classified as adjacent network, meaning the attacker must be within radio range or share the same Layer 2 broadcast domain as the target. No user interaction is required, and the impact spans confidentiality, integrity, and availability. The exploit is constrained by the requirement for low-level privileges, which in this context typically corresponds to an associated wireless client.
Root Cause
The root cause is improper validation of length or size parameters before copying data into a heap-allocated buffer inside the AP driver. When attacker-controlled input exceeds the expected size, the driver writes past the buffer boundary, corrupting adjacent heap metadata or function pointers. MediaTek's advisory references Patch ID WCNCR00480138, which implements the necessary bounds checks.
Attack Vector
An attacker positioned on the wireless network as an associated or associating client crafts malicious frames that the AP driver parses. The malformed input triggers the overflow during driver-side processing, corrupting heap memory. With careful heap shaping, the attacker can convert the corruption into arbitrary code execution within the AP firmware. Devices using the affected MediaTek chipsets as Wi-Fi access points or mesh nodes are the primary targets.
No public proof-of-concept code is available for CVE-2026-20452 at the time of publication. Technical details beyond the vendor bulletin have not been released. Refer to the MediaTek Product Security Bulletin for vendor-supplied information.
Detection Methods for CVE-2026-20452
Indicators of Compromise
- Unexpected reboots, kernel panics, or driver crashes on MediaTek-based access points and routers
- Anomalous wireless management frames or oversized fields originating from associated clients
- Unauthorized configuration changes or new processes on AP firmware following client association events
Detection Strategies
- Monitor syslog and remote logging streams from access points for WLAN driver fault traces or repeated client disassociations tied to a single MAC address
- Inspect wireless IDS/WIPS telemetry for malformed 802.11 frames targeting affected MediaTek chipsets
- Correlate firmware version inventory with the affected chipset list to identify exposed devices across the fleet
Monitoring Recommendations
- Centralize AP and router logs into a SIEM and alert on driver-level errors referencing the WLAN AP module
- Track wireless client behavior for repeated association attempts followed by AP instability
- Baseline normal management frame patterns to surface deviations consistent with overflow attempts
How to Mitigate CVE-2026-20452
Immediate Actions Required
- Identify all network devices using affected MediaTek chipsets (MT6890, MT7615, MT7915, MT7916, MT7981, MT7986, MT7990, MT7992, MT7993)
- Apply firmware updates from device OEMs that incorporate MediaTek Patch ID WCNCR00480138 as soon as they are available
- Restrict wireless network access using strong WPA3 authentication and segment guest networks from management infrastructure
- Disable unused radios or AP functionality on devices that do not require wireless serving
Patch Information
MediaTek has released a fix tracked as Patch ID WCNCR00480138 (Issue ID MSV-6295) in the June 2026 Product Security Bulletin. Device manufacturers using affected chipsets must integrate the patch into their firmware releases. Refer to the MediaTek Product Security Bulletin and contact the device OEM for firmware availability.
Workarounds
- Limit wireless association to known, trusted client MAC addresses where feasible to reduce exposure to adjacent attackers
- Place vulnerable access points behind network segmentation that isolates them from sensitive management and production assets
- Enable wireless intrusion prevention features to drop malformed management frames before they reach affected drivers
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
