CVE-2025-20715 is a security vulnerability classified under CWE-787 (Out-of-bounds Write) affecting multiple MediaTek wireless chipset models, including MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, and MT7986. The vulnerability exists in the WLAN Access Point (AP) driver due to an incorrect bounds check, which can lead to an out-of-bounds write operation. This type of memory corruption flaw can allow an attacker to overwrite adjacent memory, potentially leading to privilege escalation or system instability. The vulnerability requires the attacker to have already obtained System-level privileges on the device, meaning it is not exploitable remotely or by unprivileged users. No user interaction is needed to exploit the flaw once System access is achieved. The affected software versions include SDK release 7.6.7.2 and earlier, as well as openWRT 19.07 and 21.02 for the MT6890 chipset. Although no public exploits have been reported, the vulnerability poses a risk of local privilege escalation, which could be leveraged to gain higher control over the device or execute arbitrary code with elevated privileges. The vendor has assigned a patch ID (WCNCR00421152) and issue ID (MSV-3731), but no patch links are currently provided. The lack of a CVSS score indicates that the vulnerability is still under evaluation or that the vendor has not yet published a severity rating. The vulnerability impacts the confidentiality, integrity, and availability of affected devices by enabling attackers to manipulate system memory beyond intended boundaries, potentially leading to system compromise or denial of service.

For European organizations, the impact of CVE-2025-20715 could be significant, especially for those relying on networking equipment or IoT devices powered by the affected MediaTek chipsets. Privilege escalation vulnerabilities in WLAN AP drivers can allow attackers who have already gained some level of access to fully compromise the device, potentially leading to unauthorized access to network traffic, disruption of network services, or pivoting to other internal systems. This risk is heightened in environments where devices run outdated SDKs or openWRT versions, which are common in embedded systems and custom networking hardware. Critical infrastructure sectors such as telecommunications, manufacturing, and smart city deployments in Europe may be particularly vulnerable if they use affected hardware. Additionally, the vulnerability could be exploited to undermine network security controls, leading to data breaches or service outages. Although exploitation requires prior System privileges, the flaw lowers the barrier for attackers to gain full control, increasing the overall risk posture of affected organizations.

European organizations should take proactive steps to mitigate this vulnerability. First, they should inventory all devices and systems using the affected MediaTek chipsets and verify the firmware or SDK versions in use. Immediate action should be taken to update to patched versions once MediaTek releases them, or apply vendor-provided firmware updates for devices running openWRT 19.07 or 21.02. Until patches are available, organizations should restrict local access to affected devices, enforce strict access controls, and monitor for unusual activity indicative of privilege escalation attempts. Network segmentation can limit the impact of a compromised device. Additionally, organizations should implement robust endpoint detection and response (EDR) solutions to detect anomalous behavior at the system level. Regular security audits and penetration testing focusing on local privilege escalation vectors can help identify and remediate weaknesses. Finally, maintaining an up-to-date asset management system will facilitate rapid response to such vulnerabilities in the future.