CVE-2025-20713 is a stack overflow vulnerability classified under CWE-121, found in the WLAN AP driver software of several MediaTek chipsets: MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, and MT7986. The vulnerability stems from an incorrect bounds check in the driver code, which allows an out-of-bounds write on the stack. This memory corruption can lead to local escalation of privilege, enabling an attacker who already has System-level privileges to gain higher control or execute arbitrary code with elevated rights. The flaw does not require user interaction, increasing the risk of automated or stealthy exploitation. The affected versions include SDK release 7.6.7.2 and earlier, as well as openWRT versions 19.07 and 21.02 for MT6890. The CVSS v3.1 score is 7.8, indicating high severity, with attack vector local, low attack complexity, requiring low privileges, no user interaction, and impacting confidentiality, integrity, and availability. While no known exploits are currently reported in the wild, the vulnerability represents a significant risk due to the widespread use of these chipsets in wireless access points and embedded devices. The issue was reserved in November 2024 and published in October 2025, with MediaTek assigning the patch ID WCNCR00432661 and issue ID MSV-3904. The vulnerability's exploitation could allow attackers to bypass security controls and compromise device functionality or data integrity.

For European organizations, the impact of CVE-2025-20713 can be substantial, especially for those relying on MediaTek-based wireless access points, IoT devices, or embedded systems in critical infrastructure, telecommunications, or enterprise networks. Successful exploitation could lead to local privilege escalation, enabling attackers to gain full control over affected devices, potentially leading to unauthorized access to sensitive data, disruption of network services, or pivoting to other internal systems. The compromise of wireless infrastructure components could degrade network availability and integrity, impacting business operations and service delivery. Given the high confidentiality, integrity, and availability impact, organizations could face operational disruptions, data breaches, and compliance violations under GDPR if personal data is exposed. The lack of user interaction requirement increases the risk of automated attacks within compromised environments. Although exploitation requires some level of existing privilege, insider threats or attackers who have gained initial footholds could leverage this vulnerability to escalate privileges and deepen their access.

European organizations should immediately identify devices using the affected MediaTek chipsets and verify firmware or driver versions against the vulnerable releases (SDK 7.6.7.2 and earlier, openWRT 19.07 and 21.02 for MT6890). Applying the official MediaTek patch referenced by patch ID WCNCR00432661 as soon as it becomes available is critical. Where patches are not yet available, organizations should implement strict access controls to limit local administrative access to trusted personnel only, reducing the risk of exploitation. Network segmentation can help isolate vulnerable devices from critical systems. Monitoring for unusual local privilege escalation attempts or anomalous behavior on devices with these chipsets is recommended. Employing endpoint detection and response (EDR) solutions capable of detecting stack overflow exploitation techniques can provide early warning. For embedded devices or IoT, consider firmware integrity verification and secure boot mechanisms to prevent unauthorized code execution. Additionally, coordinate with vendors and supply chain partners to ensure timely updates and vulnerability management. Finally, update incident response plans to include scenarios involving local privilege escalation on wireless infrastructure devices.