CVE-2025-20751 is a security vulnerability classified under CWE-787 (Out-of-bounds Write) affecting multiple MediaTek modem chipsets, including MT2735, MT6833 series, MT6853 series, MT6873 series, MT6880 series, MT6890 series, MT8675, MT8771, MT8791 series, and MT8797. The flaw arises from a missing bounds check in the modem firmware (Modem NR15), which can be exploited remotely by an attacker controlling a rogue base station. When a user equipment (UE) connects to such a malicious base station, the out-of-bounds write can cause the modem system to crash, resulting in a denial of service condition. This attack vector requires no user interaction and no elevated privileges, making it relatively straightforward to exploit in environments where an attacker can simulate or control a base station. The vulnerability impacts the availability of the device's modem functionality, potentially disrupting cellular connectivity. Although no exploits are currently known in the wild, the vulnerability is publicly disclosed and a patch (MOLY01661195) has been identified by MediaTek. The broad range of affected chipsets indicates a wide potential impact across many mobile devices using MediaTek modems. The vulnerability's root cause is a classic memory safety error, which can be leveraged to destabilize the modem subsystem. This could affect mobile devices in consumer, enterprise, and critical infrastructure contexts that rely on cellular connectivity for communication and operations.

For European organizations, the primary impact of CVE-2025-20751 is the potential for remote denial of service on devices using affected MediaTek modem chipsets. This can disrupt cellular network connectivity, impacting communication, data transfer, and operational continuity for mobile workforce, IoT devices, and critical infrastructure relying on cellular networks. Enterprises with mobile-dependent operations, such as logistics, emergency services, and remote monitoring, may experience service outages or degraded performance. The vulnerability could also be exploited in targeted attacks by adversaries controlling rogue base stations, potentially causing localized network disruptions. While confidentiality and integrity impacts are not indicated, availability degradation can have cascading effects on business processes and safety-critical systems. The lack of required user interaction and privileges lowers the barrier for exploitation, increasing risk. European telecom providers and device manufacturers may face increased support and remediation demands. The threat is particularly relevant in urban and industrial environments where attackers could deploy rogue base stations. Overall, the vulnerability poses a significant operational risk to European organizations relying on affected MediaTek-based devices for cellular connectivity.

To mitigate CVE-2025-20751, European organizations should prioritize the following actions: 1) Coordinate with device manufacturers and mobile network operators to obtain and deploy the official MediaTek patch (MOLY01661195) as soon as it becomes available. 2) Implement network monitoring solutions capable of detecting rogue base stations or anomalous cellular network behavior, leveraging IMSI catchers detection tools and radio frequency monitoring. 3) Enforce strict device management policies to ensure that only updated and patched devices are used within corporate environments. 4) Educate users and IT staff about the risks of connecting to untrusted cellular networks and encourage the use of VPNs or secure communication channels where possible. 5) Collaborate with telecom providers to enhance base station authentication and network integrity measures to reduce the feasibility of rogue base station attacks. 6) For critical infrastructure and IoT deployments, consider multi-network redundancy or fallback mechanisms to maintain connectivity if cellular service is disrupted. 7) Regularly audit and update device firmware and software to maintain security posture. These measures go beyond generic advice by focusing on proactive detection of rogue infrastructure and strict patch management tailored to the specific MediaTek vulnerability.