CVE-2025-20715 is a vulnerability classified as CWE-787 (Out-of-bounds Write) found in the WLAN AP driver of several MediaTek chipsets including MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, and MT7986. The root cause is an incorrect bounds check in the driver code, which allows an attacker with local system privileges to perform an out-of-bounds write operation. This memory corruption can lead to escalation of privileges beyond the current system level, potentially enabling an attacker to execute arbitrary code with elevated privileges or cause denial of service conditions. The vulnerability does not require user interaction and has a CVSS v3.1 score of 7.8, indicating high severity. Affected versions include SDK release 7.6.7.2 and earlier, as well as openWRT 19.07 and 21.02 on MT6890 devices. While no public exploits are known, the vulnerability's nature and impact make it a significant risk for embedded systems and wireless infrastructure relying on these chipsets. The issue was assigned by MediaTek and publicly disclosed in October 2025, with a patch identified as WCNCR00421152, though no direct patch links are provided in the data.

For European organizations, this vulnerability poses a significant risk to the security of wireless access points and embedded devices using affected MediaTek chipsets. Successful exploitation could allow attackers who have already compromised system-level access to further escalate privileges, potentially gaining full control over the device. This could lead to unauthorized access to sensitive network traffic, disruption of wireless services, and pivoting deeper into corporate networks. Given the widespread use of MediaTek chipsets in consumer and enterprise-grade wireless equipment, the vulnerability could impact sectors such as telecommunications, manufacturing, healthcare, and critical infrastructure. The lack of required user interaction and relatively low complexity of exploitation (local privilege required) means that insider threats or malware with system privileges could leverage this flaw to solidify persistence and expand control. The confidentiality, integrity, and availability of network communications and connected systems could be severely compromised, leading to data breaches, service outages, and reputational damage.

European organizations should prioritize applying the official patches from MediaTek (WCNCR00421152) as soon as they become available. In the interim, organizations should audit their environments to identify devices using the affected MediaTek chipsets and SDK versions, particularly those running openWRT 19.07 or 21.02 on MT6890. Restrict local system access to trusted administrators only and implement strict access controls to prevent unprivileged users or malware from gaining system privileges. Network segmentation should be enforced to isolate vulnerable devices from critical infrastructure. Employ runtime protections such as memory protection mechanisms and integrity monitoring on embedded devices where feasible. Regularly monitor device logs and network traffic for anomalous behavior indicative of exploitation attempts. Coordinate with device vendors and suppliers to ensure firmware updates are deployed promptly. Finally, consider replacing legacy devices that cannot be updated with more secure alternatives.