CVE-2025-20711 is a vulnerability classified under CWE-787 (Out-of-bounds Write) found in the WLAN Access Point (AP) driver of several MediaTek chipsets: MT6890, MT7916, MT7981, and MT7986. The root cause is an incorrect bounds check in the driver code, which allows an attacker positioned within proximal or adjacent wireless range to perform an out-of-bounds write operation. This memory corruption flaw can be exploited to escalate privileges remotely without requiring any prior authentication or user interaction, making it particularly dangerous in wireless environments. The affected software versions include MediaTek SDK release 7.6.7.2 and earlier, as well as OpenWrt versions 19.07 and 21.02 running on MT6890 hardware. Successful exploitation can lead to complete compromise of the device’s confidentiality, integrity, and availability, potentially allowing attackers to execute arbitrary code or disrupt device operations. The vulnerability has been assigned a CVSS v3.1 base score of 8.8, indicating high severity with attack vector as adjacent network, low attack complexity, no privileges required, and no user interaction needed. Although no known exploits have been observed in the wild yet, the vulnerability’s characteristics make it a significant risk for wireless infrastructure relying on these chipsets. The vendor has acknowledged the issue (Issue ID MSV-3748) and assigned a patch ID (WCNCR00422399), but no public patch links are currently available. This vulnerability is particularly relevant for embedded wireless devices, IoT gateways, and access points using MediaTek hardware, which are common in both consumer and enterprise environments.

For European organizations, the impact of CVE-2025-20711 is substantial due to the widespread use of MediaTek chipsets in wireless access points, IoT devices, and embedded systems across various sectors including telecommunications, manufacturing, smart cities, and critical infrastructure. Exploitation could allow attackers within wireless range to escalate privileges on affected devices, potentially leading to unauthorized access to internal networks, interception or manipulation of sensitive data, and disruption of network availability. This risk is heightened in environments with dense wireless deployments or where physical proximity to devices is feasible, such as office buildings, industrial sites, or public spaces. The compromise of wireless infrastructure could facilitate lateral movement within networks, enabling further attacks on critical systems. Additionally, the lack of required authentication or user interaction lowers the barrier for attackers, increasing the likelihood of exploitation. The vulnerability could also impact supply chain security if affected devices are integrated into larger systems. Overall, the threat poses a significant risk to the confidentiality, integrity, and availability of networked systems in Europe, necessitating urgent attention from security teams.

1. Monitor MediaTek and OpenWrt vendor channels closely for official patches addressing CVE-2025-20711 and apply them immediately upon release. 2. Until patches are available, implement strict wireless network segmentation to isolate vulnerable devices from critical network segments. 3. Restrict wireless access to trusted devices by enforcing strong authentication mechanisms such as WPA3 and MAC address filtering. 4. Deploy wireless intrusion detection/prevention systems (WIDS/WIPS) to detect anomalous activity indicative of exploitation attempts near access points. 5. Regularly audit and update firmware on all devices using affected MediaTek chipsets to ensure they are running the latest secure versions. 6. Limit physical access to wireless infrastructure to reduce the risk of proximal attackers. 7. Employ network anomaly detection tools to identify unusual traffic patterns or privilege escalations originating from wireless devices. 8. Educate IT and security staff about the vulnerability’s characteristics to improve incident response readiness. 9. For organizations using OpenWrt-based devices, consider upgrading to versions beyond 21.02 or applying community patches if available. 10. Engage with device vendors and suppliers to confirm the status of affected hardware and firmware and plan for device replacement if patches are not forthcoming.