CVE-2025-20720 is a heap overflow vulnerability classified under CWE-122 found in the WLAN Access Point (AP) driver of several MediaTek chipsets, including MT6890, MT7603, MT7615, MT7622, MT7915, MT7916, MT7981, and MT7986. The root cause is an incorrect bounds check in the driver code that leads to an out-of-bounds write on the heap memory. This memory corruption can be triggered remotely by an attacker within wireless range (proximal or adjacent), without requiring any authentication or user interaction. The vulnerability allows escalation of privileges on the affected device, potentially enabling the attacker to execute arbitrary code or disrupt device operations. The affected software versions include SDK release 7.6.7.2 and earlier, and OpenWrt versions 19.07 and 21.02 for the MT6890 chipset. The vulnerability has a CVSS v3.1 base score of 8.8, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. Although no known exploits are currently in the wild, the vulnerability poses a significant risk to devices using these MediaTek chipsets, especially wireless access points and embedded systems in network infrastructure. The issue is tracked under MediaTek’s internal ID MSV-3569 and patch ID WCNCR00418954, but no public patch links are currently available. The vulnerability’s exploitation could lead to full device compromise, enabling attackers to intercept or manipulate network traffic, disrupt wireless services, or pivot into internal networks.

For European organizations, the impact of CVE-2025-20720 could be substantial, particularly for those relying on wireless infrastructure or embedded devices powered by the affected MediaTek chipsets. Compromise of WLAN AP drivers could lead to unauthorized access to sensitive internal networks, data breaches, and disruption of critical services. This is especially concerning for sectors such as telecommunications, government, finance, healthcare, and critical infrastructure where wireless connectivity is integral. The ability to escalate privileges remotely without authentication or user interaction increases the risk of widespread exploitation in dense urban or enterprise environments. Additionally, compromised devices could be used as footholds for lateral movement or as part of botnets, amplifying the threat landscape. The absence of public exploits currently provides a window for proactive mitigation, but the high CVSS score and ease of exploitation necessitate urgent attention to patching and network defense strategies.

1. Monitor MediaTek and OpenWrt vendor advisories closely for official patches addressing CVE-2025-20720 and apply them immediately upon release. 2. For devices where patches are not yet available, implement network segmentation to isolate vulnerable wireless access points and embedded devices from critical internal networks. 3. Employ wireless intrusion detection and prevention systems (WIDS/WIPS) to detect anomalous or malicious wireless activity indicative of exploitation attempts. 4. Restrict physical proximity access to wireless infrastructure to trusted personnel and secure wireless environments to reduce the risk of proximal attacks. 5. Regularly audit and update firmware on all affected devices to minimize exposure. 6. Use strong wireless encryption and authentication mechanisms to limit unauthorized access, although this vulnerability does not require authentication to exploit. 7. Implement network-level monitoring and logging to detect unusual privilege escalations or device behavior that may indicate exploitation. 8. Consider deploying endpoint detection and response (EDR) solutions on critical devices to identify and contain potential compromises early.