CVE-2025-61609 is a vulnerability identified in the modem components of Unisoc (Shanghai) Technologies Co., Ltd. chipsets T8100, T9100, T8200, and T8300, which are integrated into mobile devices running Android versions 13 through 16. The root cause is improper input validation (CWE-20) within the modem firmware or software stack. This flaw allows an unauthenticated remote attacker to send specially crafted input to the modem, triggering a system crash. The crash leads to a denial of service (DoS) condition, disrupting device availability without granting any additional execution privileges or compromising confidentiality or integrity. The attack vector is network-based (AV:N), requires no privileges (PR:N), and no user interaction (UI:N), making it relatively easy to exploit remotely. The vulnerability was published on December 1, 2025, with a CVSS v3.1 base score of 7.5, categorized as high severity. No patches or exploits are currently publicly available, but the potential for disruption in mobile communications is significant, especially for devices relying on these Unisoc chipsets. The vulnerability underscores the importance of robust input validation in modem firmware to prevent remote DoS attacks.

For European organizations, the primary impact of CVE-2025-61609 is the potential disruption of mobile device availability due to remote denial of service attacks targeting Unisoc modem chipsets. This can affect employees' mobile communications, IoT devices, and critical infrastructure components that rely on cellular connectivity. Industries such as telecommunications, emergency services, transportation, and utilities could experience operational interruptions if devices become unresponsive. Although the vulnerability does not compromise data confidentiality or integrity, the loss of availability can degrade business continuity and service reliability. The ease of exploitation without authentication or user interaction increases the risk of widespread attacks, especially in environments with high mobile device usage. Additionally, organizations using mobile endpoints for remote work or critical communications may face increased vulnerability exposure. The absence of known exploits currently provides a window for proactive mitigation, but the threat landscape could evolve rapidly.

1. Monitor Unisoc and device manufacturers for official patches or firmware updates addressing CVE-2025-61609 and apply them promptly once available. 2. Implement network-level protections such as intrusion detection/prevention systems (IDS/IPS) to detect and block anomalous or malformed modem traffic that could trigger the vulnerability. 3. Employ mobile device management (MDM) solutions to enforce security policies and remotely manage device updates and configurations. 4. Limit exposure of vulnerable devices to untrusted networks by enforcing network segmentation and restricting unnecessary inbound modem traffic. 5. Conduct regular security assessments and penetration testing focusing on cellular modem interfaces to identify potential exploitation attempts. 6. Educate IT and security teams about the vulnerability to ensure rapid incident response if signs of exploitation emerge. 7. For critical infrastructure, consider deploying redundant communication channels to maintain availability in case of modem DoS events. 8. Collaborate with telecom providers to monitor network traffic patterns for unusual activity targeting Unisoc-based devices.