CVE-2025-20711 is a vulnerability identified in the WLAN Access Point (AP) driver of several MediaTek chipsets: MT6890, MT7916, MT7981, and MT7986. The root cause is an out-of-bounds write triggered by an incorrect bounds check in the driver code. This flaw allows an attacker positioned proximally or adjacent on the network to perform a remote escalation of privilege without needing any additional execution privileges, authentication, or user interaction. The vulnerability affects SDK release 7.6.7.2 and earlier, including OpenWrt versions 19.07 and 21.02 for the MT6890 chipset. The CVSS v3.1 base score is 8.8, reflecting high severity with attack vector being adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). This means an attacker within wireless range can exploit the flaw to gain elevated privileges on the device, potentially leading to full device compromise. The vulnerability is tracked under CWE-1287, which relates to improper bounds checking leading to memory corruption. Although no exploits have been reported in the wild yet, the technical details and severity indicate a significant risk for devices using these chipsets in wireless infrastructure. The issue has been assigned a patch ID (WCNCR00422399) by MediaTek, but no public patch links are currently available. Organizations using affected MediaTek chipsets in their wireless access points or embedded systems should monitor for patches and apply them promptly to mitigate risk.

The impact of CVE-2025-20711 on European organizations can be substantial, especially for those relying on MediaTek-based wireless access points or embedded devices in their network infrastructure. Successful exploitation allows an attacker within wireless range to escalate privileges remotely without authentication or user interaction, potentially leading to full compromise of affected devices. This can result in unauthorized access to sensitive data, disruption of network services, and the ability to pivot within internal networks. Given the widespread use of MediaTek chipsets in IoT devices, routers, and embedded systems, the vulnerability poses a risk to operational continuity and data confidentiality. Critical sectors such as telecommunications, manufacturing, and smart city infrastructure in Europe could be particularly affected. The vulnerability's ease of exploitation and high impact on confidentiality, integrity, and availability elevate the threat level. Additionally, the lack of known exploits currently provides a window for proactive mitigation before active attacks emerge.

To mitigate CVE-2025-20711, European organizations should: 1) Monitor MediaTek and OpenWrt vendor advisories closely for official patches addressing this vulnerability and apply them immediately upon release. 2) Where patches are not yet available, implement network segmentation to isolate vulnerable devices and restrict wireless access to trusted clients only. 3) Employ wireless intrusion detection and prevention systems (WIDS/WIPS) to detect anomalous activity in the wireless environment that could indicate exploitation attempts. 4) Disable or limit unnecessary wireless services and features on affected devices to reduce the attack surface. 5) Conduct regular firmware audits to identify devices running vulnerable SDK or OpenWrt versions and plan for timely upgrades or replacements. 6) Enforce strict physical security controls to prevent attackers from gaining proximal access to wireless networks. 7) Educate IT and security teams about the nature of this vulnerability to ensure rapid response capability. These targeted actions go beyond generic advice by focusing on the specific attack vector (adjacent wireless network) and the affected device ecosystem.