CVE-2025-20752 is a security vulnerability classified under CWE-617 (Reachable Assertion) affecting numerous MediaTek modem chipsets, including models MT2735 through MT8791T. The vulnerability stems from a missing bounds check in the modem firmware, which can cause the system to hit an assertion failure and crash. This flaw can be triggered remotely without any user interaction or elevated privileges by forcing a user equipment (UE) to connect to a maliciously controlled rogue base station. The attack vector exploits the modem's handling of network signals and data, leading to a denial of service (DoS) condition by crashing the modem subsystem. The affected modem versions include NR15, NR16, NR17, and NR17R firmware releases. Although no exploits have been reported in the wild, the vulnerability poses a significant risk to the availability of mobile devices and services relying on these chipsets. The issue was reserved in November 2024 and published in December 2025, with a patch identified internally (MOLY01270690; Issue ID MSV-4301), though no public patch link is provided. This vulnerability is particularly concerning because it requires no user interaction and no additional execution privileges, making it easier to exploit in hostile network environments. The broad range of affected chipsets indicates a widespread potential impact across many device manufacturers using MediaTek modems.

For European organizations, this vulnerability could disrupt mobile communications by causing modem crashes and denial of service on devices using affected MediaTek chipsets. Critical sectors such as telecommunications providers, emergency services, and enterprises relying on mobile connectivity for operations could experience outages or degraded service quality. The ability to trigger the vulnerability remotely via rogue base stations means attackers could target specific geographic areas or user groups, potentially impacting mobile network reliability and availability. This could also affect IoT devices, industrial control systems, and mobile endpoints that incorporate these modems, leading to broader operational disruptions. The lack of required user interaction or elevated privileges lowers the barrier for exploitation, increasing the risk of widespread attacks. Additionally, the presence of rogue base stations in urban or high-value areas could facilitate targeted denial of service campaigns against key infrastructure or organizations. The vulnerability may also undermine trust in mobile network security and complicate compliance with European data protection and service availability regulations.

European organizations should prioritize obtaining and deploying the official firmware updates from device manufacturers or MediaTek as soon as they become available to address this vulnerability. Network operators should enhance detection and mitigation capabilities against rogue base stations by implementing advanced base station authentication, anomaly detection, and signal monitoring tools. Enterprises should consider deploying mobile threat defense solutions that can detect suspicious network behavior and isolate affected devices. For critical infrastructure and sensitive environments, restricting device connectivity to trusted networks and employing network segmentation can reduce exposure. Security teams should monitor for unusual modem crashes or connectivity issues that may indicate exploitation attempts. Collaboration with mobile network operators to share threat intelligence and coordinate responses to rogue base station activity is recommended. Additionally, organizations should review device procurement policies to assess the risk associated with MediaTek-based devices and consider alternative hardware if feasible. Finally, raising user awareness about the risks of connecting to untrusted networks can help reduce inadvertent exposure.