CVE-2025-20761 is a vulnerability identified in a broad range of MediaTek modem chipsets, including models MT2735 through MT8893, affecting modem versions NR15, NR16, and NR17. The root cause is an improper check for unusual or exceptional conditions (CWE-754) within the modem's error handling logic. Specifically, when a user equipment (UE) device connects to a rogue base station controlled by an attacker, the modem may incorrectly handle error conditions, leading to a system crash. This crash results in a denial of service (DoS) condition on the affected device. The vulnerability does not require any additional execution privileges or user interaction, making it remotely exploitable by an attacker capable of setting up or controlling a rogue base station. The flaw affects the modem firmware responsible for managing cellular connections, which is critical for maintaining network availability and device functionality. While no public exploits are currently known, the potential for disruption is significant due to the widespread deployment of these MediaTek chipsets in mobile devices globally. The vulnerability was reserved in November 2024 and published in January 2026, with a patch identified as MOLY01311265. However, no CVSS score has been assigned yet, and no exploit code has been publicly disclosed. The issue is particularly concerning for environments where mobile connectivity is essential, such as enterprise communications, emergency services, and IoT deployments relying on cellular networks.

For European organizations, the primary impact of CVE-2025-20761 is the potential for remote denial of service attacks against devices using affected MediaTek modems. This can disrupt mobile communications, leading to loss of connectivity for employees, customers, or critical systems relying on cellular networks. Telecommunications providers could see network instability or increased support costs due to affected user devices. Enterprises using mobile broadband for remote sites or IoT devices may experience outages, impacting operational continuity. The vulnerability could also be exploited to target specific high-value individuals or organizations by deploying rogue base stations in proximity, causing targeted service disruption. Given the lack of required user interaction and no need for elevated privileges, the attack surface is broad, increasing the risk of widespread impact. Additionally, critical infrastructure sectors such as healthcare, transportation, and public safety that depend on reliable mobile communications may face operational risks. The economic and reputational damage from service outages could be significant, especially if exploited at scale or during critical events.

To mitigate CVE-2025-20761, European organizations should prioritize the following actions: 1) Apply the official MediaTek patch MOLY01311265 as soon as it becomes available and validated by device manufacturers. 2) Coordinate with mobile device vendors and telecom providers to ensure firmware updates are deployed promptly across all affected devices. 3) Implement network monitoring solutions capable of detecting rogue base stations or unusual cellular network behavior, leveraging anomaly detection and threat intelligence feeds. 4) Employ mobile device management (MDM) solutions to enforce security policies and facilitate rapid patch deployment. 5) Educate users and IT staff about the risks of connecting to untrusted cellular networks, especially in high-risk environments. 6) For critical infrastructure, consider redundant communication channels to maintain connectivity if cellular networks are disrupted. 7) Collaborate with telecom operators to enhance base station authentication and validation mechanisms to reduce the feasibility of rogue base station attacks. 8) Regularly audit and update security configurations on mobile devices and network infrastructure to minimize exposure. These measures go beyond generic advice by focusing on coordinated patch management, network-level detection, and operational resilience.