CVE-2025-20762 is a vulnerability classified under CWE-617 (Reachable Assertion) affecting multiple MediaTek modem chipsets, including MT6835, MT6878, MT6897, MT6991, MT8676, MT8755, MT8792, MT8863, and others. The vulnerability stems from improper error handling in the modem firmware (Modem NR17), which can cause the system to hit an assertion failure and crash. This crash results in a denial of service condition on the affected device. The attack vector involves a user equipment (UE) connecting to a rogue base station controlled by an attacker. Because the assertion is reachable without requiring additional execution privileges or user interaction, the vulnerability can be exploited remotely and silently. The flaw compromises device availability by causing system crashes, potentially disrupting communications. While no known exploits have been reported in the wild, the vulnerability is significant due to the widespread use of MediaTek chipsets in mobile devices and IoT equipment. The patch identified as MOLY01685181 addresses this issue, though no direct patch links were provided. The vulnerability highlights risks in cellular modem firmware, especially in environments where attackers can deploy rogue base stations to intercept or disrupt mobile communications.

For European organizations, the primary impact of CVE-2025-20762 is the potential for remote denial of service on devices using affected MediaTek chipsets. This can disrupt mobile communications, impacting business operations, especially for sectors relying on mobile connectivity such as telecommunications providers, emergency services, transportation, and critical infrastructure. The vulnerability could be exploited to cause widespread outages if attackers deploy rogue base stations in targeted areas. This risk is heightened in urban centers and industrial zones with dense mobile device usage. Additionally, IoT devices using these chipsets could be rendered inoperable, affecting automation and monitoring systems. The lack of required user interaction or privileges lowers the barrier for exploitation, increasing the threat level. Although no exploits are currently known, the potential for service disruption and operational impact is significant, necessitating proactive mitigation to maintain network reliability and security.

1. Apply firmware updates and patches from MediaTek or device manufacturers as soon as they become available, specifically the patch identified as MOLY01685181. 2. Network operators should implement detection and mitigation mechanisms against rogue base stations, such as anomaly detection systems and secure base station authentication protocols. 3. Employ mobile device management (MDM) solutions to monitor and enforce firmware update compliance across organizational devices. 4. For critical infrastructure, consider deploying redundant communication channels to maintain availability in case of targeted DoS attacks. 5. Educate security teams about the risks of rogue base stations and monitor for unusual network behavior indicative of such attacks. 6. Collaborate with telecom providers to ensure network-level protections and rapid incident response capabilities. 7. Conduct regular security assessments of mobile and IoT devices to identify vulnerable hardware and prioritize remediation. 8. Limit exposure by restricting device connectivity to trusted networks where feasible.