CVE-2025-20708 is a critical security vulnerability identified in various MediaTek modem chipsets, including models MT2735 through MT8893 and others, affecting modem firmware versions NR15, NR16, NR17, and NR17R. The vulnerability is classified as CWE-787, an out-of-bounds write, which occurs due to an incorrect bounds check in the modem's code. This flaw allows an attacker controlling a rogue base station to perform a remote escalation of privilege on a user equipment (UE) device using the affected MediaTek modem. Exploitation does not require any additional execution privileges or user interaction, making it particularly dangerous. The attacker can send specially crafted signals from the rogue base station to trigger the out-of-bounds write, potentially leading to arbitrary code execution or corruption of memory within the modem's firmware. This could compromise the confidentiality, integrity, and availability of the modem's operations, potentially allowing interception or manipulation of communications, denial of service, or further compromise of the device's operating system. The vulnerability is present in a broad range of MediaTek modem chipsets widely used in smartphones, IoT devices, and other connected hardware. Although no known exploits are currently reported in the wild, the vulnerability's nature and ease of exploitation via a rogue base station pose a significant risk. A patch identified as MOLY01123853 has been issued by MediaTek to address this issue, but deployment depends on device manufacturers and carriers updating their firmware accordingly.

For European organizations, the impact of CVE-2025-20708 can be substantial. Many enterprises and consumers rely on devices powered by MediaTek modems for mobile connectivity, including smartphones, IoT devices, and embedded systems. Successful exploitation could allow attackers to gain elevated privileges on devices remotely, bypassing typical security controls without user interaction. This could lead to interception of sensitive communications, unauthorized data access, or disruption of critical services relying on mobile networks. In sectors such as finance, healthcare, and critical infrastructure, compromised devices could serve as entry points for broader network intrusions or data breaches. Additionally, the ability to exploit this vulnerability via a rogue base station means attackers could target devices in specific geographic locations, such as corporate campuses or public spaces, increasing the risk of targeted attacks. The lack of user interaction requirement and the remote nature of the exploit make detection and prevention more challenging. Organizations may face regulatory and compliance risks if personal or sensitive data is exposed due to this vulnerability.

To mitigate CVE-2025-20708 effectively, European organizations should take a multi-layered approach: 1) Ensure that all devices using affected MediaTek modems receive firmware updates containing the MOLY01123853 patch as soon as they become available from device manufacturers or carriers. 2) Work closely with mobile network operators to monitor for and block rogue base stations within organizational premises using advanced radio frequency monitoring and intrusion detection systems. 3) Implement network segmentation and strict access controls to limit the impact of compromised devices on critical internal systems. 4) Employ endpoint detection and response (EDR) solutions capable of identifying anomalous modem or network behavior indicative of exploitation attempts. 5) Educate users about the risks of connecting to untrusted networks and encourage the use of VPNs to protect data in transit. 6) Collaborate with vendors to obtain timely security advisories and ensure rapid deployment of patches. 7) For IoT deployments, consider network-level protections such as device authentication and anomaly detection to prevent rogue device communications. These measures go beyond generic patching advice by emphasizing proactive detection of rogue base stations and network-level defenses tailored to the unique attack vector of this vulnerability.