CVE-2025-20673 is a medium severity vulnerability identified in MediaTek's WLAN STA driver affecting several wireless chipset models including MT7902, MT7921, MT7922, MT7925, and MT7927. The root cause is a NULL pointer dereference (CWE-476) that leads to an uncaught exception within the driver code. This flaw can cause the affected system to crash, resulting in a local denial of service (DoS) condition. Exploitation requires user-level execution privileges but does not require user interaction, meaning an attacker with local access can trigger the crash without additional user actions. The vulnerability affects devices running NB SDK release 3.6 and earlier versions. The CVSS v3.1 base score is 5.5, reflecting medium severity, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). No known exploits are currently reported in the wild, and no patch links are provided in the data, though a patch ID (WCNCR00413200) and issue ID (MSV-3304) are referenced. This vulnerability could be triggered by an attacker or malicious software running locally on affected devices, causing system instability or crashes, potentially disrupting wireless connectivity and dependent services.

For European organizations, the impact of CVE-2025-20673 primarily manifests as a local denial of service on devices using the affected MediaTek wireless chipsets. This could disrupt wireless network connectivity, impacting business operations reliant on Wi-Fi communication, especially in environments with many IoT or embedded devices using these chipsets. Critical infrastructure or industrial control systems employing these wireless modules could experience operational interruptions. Although the vulnerability does not allow for data theft or code execution, the availability impact could degrade productivity and cause service outages. The requirement for local privileges limits remote exploitation, but insider threats or malware with local access could leverage this vulnerability. Organizations with large deployments of affected devices may face increased risk of network instability or downtime, which could have cascading effects on business continuity and security monitoring systems.

To mitigate CVE-2025-20673, European organizations should prioritize updating affected devices to firmware or SDK versions beyond NB SDK release 3.6 where the vulnerability is patched. Since no direct patch links are provided, organizations should contact MediaTek or device vendors for the latest security updates referencing patch ID WCNCR00413200. Network administrators should implement strict access controls to limit local user privileges on devices with these chipsets, reducing the risk of local exploitation. Monitoring for unusual system crashes or wireless interface failures can help detect exploitation attempts. Employing endpoint protection solutions capable of detecting anomalous local activity and enforcing application whitelisting can further reduce risk. For critical environments, consider network segmentation to isolate vulnerable devices and reduce the impact of potential DoS conditions. Additionally, organizations should maintain an inventory of devices using these chipsets to ensure comprehensive coverage of mitigation efforts.