CVE-2026-20407 is a security vulnerability identified in the WLAN STA driver of several MediaTek wireless chipsets, specifically MT7902, MT7920, MT7921, MT7922, MT7925, and MT7927. The root cause is a missing bounds check leading to an out-of-bounds write condition (classified under CWE-787). This flaw allows a local attacker who already has user-level execution privileges on the affected system to escalate their privileges to a higher level, potentially gaining administrative or kernel-level access. Exploitation does not require user interaction, increasing the risk of automated or stealthy attacks. The vulnerability affects devices running NB SDK release 3.8 and earlier versions. Although no public exploits have been reported, the nature of the vulnerability suggests that an attacker could leverage it to compromise system integrity, execute arbitrary code, or disrupt system availability. The vulnerability is particularly relevant for devices embedding these MediaTek chipsets, such as laptops, IoT devices, and wireless communication equipment. The vendor has acknowledged the issue (Patch ID: WCNCR00464377; Issue ID: MSV-4905) but no public patch links are currently available. The absence of a CVSS score requires an assessment based on the vulnerability's characteristics, including local privilege escalation without user interaction and the potential impact on confidentiality, integrity, and availability.

For European organizations, the impact of CVE-2026-20407 can be significant, especially in environments where devices with affected MediaTek chipsets are widely deployed. The vulnerability enables local attackers to escalate privileges, which could lead to unauthorized access to sensitive data, modification or corruption of system files, and disruption of wireless communication services. This is particularly concerning for sectors such as telecommunications, manufacturing, healthcare, and critical infrastructure, where wireless connectivity is integral. Compromised devices could serve as footholds for lateral movement within corporate networks, increasing the risk of broader network compromise. Additionally, IoT devices using these chipsets may be less monitored and harder to patch, increasing exposure. The lack of user interaction required for exploitation means that attackers with local access can operate stealthily, raising the risk of undetected breaches. The overall impact includes potential data breaches, operational disruptions, and damage to organizational reputation.

1. Monitor MediaTek’s official channels closely for the release of patches addressing CVE-2026-20407 and apply them immediately upon availability. 2. Restrict local user access on devices with affected chipsets to trusted personnel only, minimizing the risk of local exploitation. 3. Implement strict endpoint security controls, including application whitelisting and behavior monitoring, to detect anomalous activities indicative of privilege escalation attempts. 4. Conduct regular audits of devices using MediaTek chipsets to identify and inventory affected hardware and software versions. 5. Employ network segmentation to isolate critical systems and reduce the potential impact of compromised devices. 6. For IoT deployments, ensure secure device management practices, including firmware update mechanisms and access controls. 7. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of applying security updates promptly. 8. Consider deploying host-based intrusion detection systems (HIDS) that can alert on suspicious local activity related to driver or kernel exploitation attempts.