CVE-2025-20667 is a high-severity vulnerability affecting a wide range of MediaTek modem chipsets, including models MT2735 through MT8797, covering many popular mobile SoCs used in smartphones and IoT devices. The vulnerability is categorized under CWE-326, indicating inadequate encryption strength. Specifically, the issue arises from incorrect error handling within the modem firmware, which can lead to information disclosure. An attacker controlling a rogue base station can exploit this flaw to remotely extract sensitive information from a user equipment (UE) device without requiring any additional execution privileges, user interaction, or authentication. The affected modem versions include LR12A, LR13, NR15, NR16, NR17, and NR17R. The vulnerability has a CVSS 3.1 score of 7.5 (high), reflecting its potential impact on confidentiality with no impact on integrity or availability. The attack vector is network-based (remote), with low attack complexity and no privileges or user interaction needed. This means that any UE connecting to a malicious base station could be compromised to leak sensitive data. The flaw stems from weak encryption or improper cryptographic error handling in the modem’s communication protocols, which are critical for securing cellular network interactions. Although no known exploits are currently reported in the wild, the broad range of affected chipsets and the ease of exploitation make this a significant threat. The vendor has reserved the issue and assigned a patch ID (MOLY01513293), indicating that a fix is or will be available. This vulnerability highlights the risks inherent in cellular modem firmware, which is often less scrutinized than application-layer software but is a critical attack surface for mobile devices.

For European organizations, the impact of CVE-2025-20667 can be substantial, especially for those relying on mobile communications for sensitive operations or using devices with MediaTek chipsets. The vulnerability enables attackers to remotely disclose sensitive information from devices connected to rogue base stations, which could include location data, subscriber identity, or other confidential information transmitted over the cellular network. This threatens the confidentiality of communications and could facilitate further targeted attacks, espionage, or data leakage. Enterprises with mobile workforces, IoT deployments, or critical infrastructure relying on cellular connectivity are at risk. The lack of required user interaction or privileges means that devices can be compromised silently, increasing the risk of undetected data breaches. Additionally, the vulnerability could undermine trust in mobile network security, impacting sectors such as finance, healthcare, and government services that depend on secure mobile communications. Given the widespread use of MediaTek chipsets in affordable smartphones popular in Europe, a large number of devices could be vulnerable, potentially affecting both corporate and consumer users. The threat also poses risks to mobile network operators and service providers who must guard against rogue base stations within their networks or geographic regions.

To mitigate CVE-2025-20667, European organizations should take a multi-layered approach: 1) Ensure that all devices using affected MediaTek chipsets receive and apply firmware updates or patches from device manufacturers or carriers as soon as they become available. Coordination with vendors to confirm patch deployment is critical. 2) Mobile network operators should enhance detection and prevention mechanisms for rogue base stations, including deploying advanced radio frequency monitoring tools and anomaly detection systems to identify unauthorized or suspicious base stations within their coverage areas. 3) Organizations should implement mobile device management (MDM) solutions that can enforce security policies, monitor device integrity, and restrict connections to untrusted networks. 4) For high-risk environments, consider using devices with modems from vendors with stronger security track records or additional hardware security features. 5) Educate users about the risks of connecting to unknown or untrusted cellular networks, although user interaction is not required for exploitation, awareness can help in some scenarios. 6) Network segmentation and encryption at higher communication layers (e.g., VPNs, application-layer encryption) can reduce the impact of any data leakage from the modem layer. 7) Collaborate with national cybersecurity agencies and telecom regulators to promote best practices and rapid incident response to rogue base station threats.