CVE-2025-20690 is a security vulnerability identified in several MediaTek wireless chipset models including MT6890, MT7615, MT7622, MT7663, MT7915, MT7916, MT7981, and MT7986. The flaw exists in the WLAN Access Point (AP) driver, where an incorrect bounds check leads to an out-of-bounds read condition (classified under CWE-125). This type of vulnerability allows an attacker with local user privileges to read memory beyond the intended buffer boundaries, potentially disclosing sensitive information from kernel or driver memory. Notably, exploitation does not require user interaction, increasing the risk of automated or stealthy attacks. The vulnerability affects devices running SDK release 7.6.7.2 and earlier, as well as openWRT versions 19.07 and 21.02, which are commonly used in embedded systems and routers incorporating these MediaTek chipsets. Although no known exploits have been reported in the wild, the flaw's presence in widely deployed wireless chipsets used in consumer and enterprise networking equipment makes it a significant concern. The vulnerability requires local user execution privileges, meaning an attacker must have some level of access to the device, but no further authentication or user action is needed to trigger the out-of-bounds read. The issue was officially published on July 8, 2025, and is tracked under MediaTek's internal issue ID MSV-3478 and patch ID WCNCR00418038. No CVSS score has been assigned yet, and no public patches or exploit code are currently available, but the vulnerability's nature suggests a need for prompt mitigation once patches are released.

For European organizations, this vulnerability poses a risk primarily to network infrastructure devices such as routers, access points, and embedded wireless systems that utilize the affected MediaTek chipsets. Successful exploitation could lead to local information disclosure, potentially exposing sensitive configuration data, cryptographic keys, or user data stored in memory. This could facilitate further attacks such as privilege escalation or lateral movement within corporate networks. Given the prevalence of openWRT-based devices and MediaTek chipsets in both consumer and enterprise-grade networking equipment across Europe, the vulnerability could impact a broad range of organizations, including SMEs and critical infrastructure operators. The lack of required user interaction and the possibility of automated exploitation increase the threat level, especially in environments where local user access is possible or where devices are inadequately segmented. Confidentiality is primarily at risk, while integrity and availability impacts are less direct but could follow from subsequent exploitation steps. The vulnerability may also affect IoT devices and embedded systems used in industrial or smart city applications, which are increasingly common in European markets, thereby expanding the potential attack surface.

European organizations should proactively identify devices using the affected MediaTek chipsets and running vulnerable SDK or openWRT versions. Network administrators should inventory and segment such devices to limit local user access and reduce exposure. Applying vendor patches promptly once available is critical; until then, consider upgrading to newer firmware versions that do not include the vulnerable driver or replacing affected hardware if feasible. Employ strict access controls and monitoring on network devices to detect unauthorized local access attempts. For openWRT-based devices, upgrading to the latest stable releases beyond 21.02 is recommended. Additionally, organizations should implement network segmentation to isolate critical infrastructure and reduce the risk of lateral movement from compromised devices. Regularly auditing device configurations and monitoring logs for anomalous behavior related to WLAN drivers can help detect exploitation attempts. Finally, educating users and administrators about the risks of local privilege misuse and enforcing least privilege principles will further reduce the attack surface.