CVE-2025-20762 is a vulnerability identified in multiple MediaTek modem chipsets, including models MT6835, MT6878, MT6897, MT6991, MT8676, MT8755, MT8792, MT8863, MT8873, and MT8883. The issue stems from a reachable assertion failure (CWE-617) caused by incorrect error handling within the modem firmware, specifically in the NR17 modem version. When a user equipment (UE) device equipped with these chipsets connects to a rogue base station controlled by an attacker, the modem may encounter an assertion failure leading to a system crash. This results in a remote denial of service (DoS) condition. Notably, exploitation does not require any privileges or user interaction, making it easier for attackers to trigger the fault remotely. The vulnerability affects the availability of the device but does not impact confidentiality or integrity. The CVSS v3.1 score is 6.5 (medium), with an attack vector of adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and impact limited to availability (A:H). Although no known exploits are currently reported in the wild, the presence of a patch (MOLY01685181) indicates that MediaTek has addressed the issue internally. This vulnerability is particularly relevant for mobile devices using these chipsets, including smartphones, IoT devices, and embedded systems that rely on cellular connectivity.

For European organizations, the primary impact of CVE-2025-20762 is the potential for remote denial of service on devices using affected MediaTek modem chipsets. This can disrupt mobile communications, affecting business operations reliant on cellular networks, such as remote work, IoT deployments, and critical communications infrastructure. Industries like telecommunications, transportation, healthcare, and emergency services could experience service interruptions if devices lose connectivity or crash unexpectedly. The vulnerability does not expose sensitive data or allow unauthorized access, but the loss of availability can degrade operational continuity and user experience. Additionally, the attack vector requires a rogue base station, which could be deployed in targeted attacks or in areas with weak network security controls. European organizations with extensive mobile device fleets or IoT ecosystems using these chipsets should be aware of the risk of service disruption and plan accordingly.

To mitigate CVE-2025-20762, European organizations should: 1) Apply the official MediaTek patch (MOLY01685181) as soon as it becomes available from device manufacturers or vendors to fix the underlying firmware issue. 2) Monitor and restrict connections to unauthorized or suspicious base stations by implementing network access controls and using mobile network anomaly detection tools. 3) Employ mobile device management (MDM) solutions to ensure devices are updated promptly and to enforce security policies. 4) Educate users and administrators about the risks of rogue base stations and encourage reporting of unusual network behavior. 5) For critical infrastructure, consider deploying additional network segmentation and redundancy to minimize impact from device outages. 6) Collaborate with mobile network operators to identify and mitigate rogue base station threats within their coverage areas. 7) Continuously monitor device logs and network traffic for signs of repeated assertion failures or crashes that could indicate exploitation attempts.