CVE-2025-20670 is a medium-severity vulnerability identified in various MediaTek modem chipsets, including models MT2737 through MT8798, affecting modem versions NR16, NR17, and NR17R. The root cause is improper certificate validation (CWE-295) within the modem firmware, which can lead to a permission bypass scenario. Specifically, if a user equipment (UE) device equipped with one of these affected MediaTek modems connects to a rogue base station controlled by an attacker, the improper validation of certificates allows the attacker to bypass normal permission checks. This can result in remote information disclosure. Exploitation requires user execution privileges and user interaction, meaning the victim must perform some action, such as connecting to a malicious network or accepting a connection, for the attack to succeed. The vulnerability does not impact confidentiality or integrity directly but affects availability, as indicated by the CVSS vector (AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H). The vulnerability is network exploitable with low attack complexity but requires privileges and user interaction. No known exploits are currently reported in the wild, and no patch links are provided in the data, although a patch ID (MOLY01334347) and issue ID (MSV-2772) are referenced. This vulnerability is significant because MediaTek chipsets are widely used in mobile devices globally, including smartphones and IoT devices, making the potential attack surface large. Attackers controlling rogue base stations could exploit this flaw to disrupt service availability or cause denial of service conditions on affected devices.

For European organizations, the impact of CVE-2025-20670 can be substantial, especially for enterprises relying on mobile communications and IoT devices powered by MediaTek chipsets. The vulnerability could be exploited in public or private cellular networks where attackers set up rogue base stations to intercept or disrupt communications. This could lead to denial of service conditions on critical mobile devices, affecting business continuity, especially for sectors dependent on mobile connectivity such as logistics, emergency services, and remote workforce operations. Although the vulnerability does not directly compromise data confidentiality or integrity, the availability impact could disrupt communications and operational processes. Additionally, the requirement for user interaction means social engineering or phishing tactics could be used to lure users into connecting to malicious networks. European organizations with employees traveling or operating in environments with less secure cellular infrastructure may be at higher risk. The widespread use of MediaTek chipsets in consumer and industrial devices across Europe increases the likelihood of exposure. Furthermore, disruption of mobile services could have cascading effects on critical infrastructure and services that rely on cellular connectivity.

To mitigate CVE-2025-20670, European organizations should implement a multi-layered approach: 1) Ensure all devices using affected MediaTek modems are updated with the latest firmware patches from device manufacturers or MediaTek as soon as they become available, referencing patch ID MOLY01334347. 2) Educate users about the risks of connecting to unknown or untrusted cellular networks, emphasizing caution when prompted to connect to new base stations or networks, especially in public or unsecured environments. 3) Deploy network monitoring solutions capable of detecting rogue base stations or anomalous cellular network behavior within organizational premises and critical operational areas. 4) For critical mobile and IoT deployments, consider using devices with alternative chipsets or additional security controls that validate cellular network authenticity more robustly. 5) Collaborate with mobile network operators to enhance detection and mitigation of rogue base stations in regions of operation. 6) Implement endpoint security solutions that can alert or block suspicious network connections initiated by the device. 7) For high-risk environments, restrict device connectivity to trusted networks using Mobile Device Management (MDM) policies or VPNs that can detect and prevent connections to unauthorized cellular networks.