CVE-2025-31717 identifies a vulnerability in the modem firmware of Unisoc (Shanghai) Technologies Co., Ltd. chipsets, specifically models T750, T765, T760, T770, T820, S8000, T8300, and T9300. These chipsets are integrated into mobile devices running Android versions 13 through 16. The root cause is improper input validation (CWE-20) within the modem’s processing of incoming data, which can be manipulated by an attacker to trigger a system crash. This crash leads to a remote denial of service (DoS) condition, disrupting device availability without requiring any authentication or user interaction. The vulnerability does not compromise confidentiality or integrity, as it does not allow code execution or data leakage. The CVSS v3.1 score is 7.5, indicating high severity primarily due to the network attack vector (AV:N), low attack complexity (AC:L), and no privileges or user interaction needed (PR:N/UI:N). Although no exploits are currently known in the wild and no patches have been published, the potential for disruption in mobile communications is significant given the widespread use of affected chipsets in consumer and enterprise devices. The vulnerability was reserved in April 2025 and published in October 2025, highlighting recent discovery and disclosure.

For European organizations, this vulnerability poses a risk mainly to availability of mobile communications and connected devices using Unisoc modem chipsets. Telecommunications providers, mobile network operators, and enterprises relying on mobile broadband for critical operations could experience service interruptions if exploited. Disruptions could affect mobile workforce connectivity, IoT deployments, and emergency communication systems. Although confidentiality and integrity are not directly impacted, the denial of service could indirectly affect operational continuity and customer trust. The lack of required authentication or user interaction means attackers can remotely target vulnerable devices at scale, potentially leading to widespread outages. The impact is heightened in sectors with high dependency on mobile connectivity such as finance, healthcare, and public safety. The absence of patches increases exposure time, necessitating proactive defensive measures.

1. Implement network-level filtering and intrusion detection systems to monitor and block suspicious traffic targeting modem interfaces, especially from untrusted sources. 2. Collaborate with device manufacturers and Unisoc to obtain and deploy firmware updates as soon as patches become available. 3. Employ mobile device management (MDM) solutions to quickly identify and isolate affected devices within organizational networks. 4. Use anomaly detection tools to monitor modem behavior for signs of crashes or instability indicative of exploitation attempts. 5. Limit exposure of vulnerable devices by restricting unnecessary remote access and disabling unused modem features. 6. Educate IT and security teams about the vulnerability to ensure rapid incident response. 7. For critical infrastructure, consider fallback communication channels to maintain operations during potential outages. 8. Engage with telecom providers to understand their mitigation strategies and coordinate defense efforts.