CVE-2026-20422 is a security vulnerability classified under CWE-617 (Reachable Assertion) affecting numerous MediaTek modem chipsets including MT2735, MT2737, MT6813, MT6815, and many others used in mobile devices. The vulnerability stems from improper input validation in the modem firmware, which can be triggered when a user equipment (UE) connects to a malicious or rogue base station controlled by an attacker. This causes the modem to hit an assertion failure, leading to a system crash and resulting in a denial of service (DoS) condition. The attack vector is remote and does not require any user interaction or elevated privileges, making it easier to exploit in the wild. The affected modem versions include NR15, NR16, NR17, and NR17R. Although no exploits have been reported publicly yet, the vulnerability could be leveraged to disrupt mobile device connectivity and availability. MediaTek has assigned patch ID MOLY00827332 to address this issue. The broad range of affected chipsets indicates a wide potential impact across many mobile devices globally. The vulnerability primarily threatens the availability of devices by causing crashes, which could impact communications, especially in environments relying heavily on mobile connectivity.

For European organizations, the primary impact of CVE-2026-20422 is the potential for remote denial of service on devices using affected MediaTek modem chipsets. This could disrupt mobile communications, affecting business operations, especially for sectors dependent on mobile networks such as telecommunications providers, emergency services, and critical infrastructure operators. The vulnerability could be exploited by attackers setting up rogue base stations to target specific users or groups, causing device crashes without requiring user interaction. This may lead to service outages, loss of connectivity, and operational disruptions. Additionally, organizations relying on mobile IoT devices or remote monitoring systems using these chipsets could experience degraded service or failure. The widespread use of MediaTek chipsets in consumer and enterprise mobile devices across Europe increases the risk of broad impact. The lack of required authentication or user action lowers the barrier for exploitation, raising concerns about potential targeted or opportunistic attacks.

European organizations should prioritize the following mitigation steps: 1) Ensure all devices using affected MediaTek modem chipsets are updated with the latest firmware patches from MediaTek, specifically patch MOLY00827332 or later versions that address this vulnerability. 2) Collaborate with mobile network operators to detect and mitigate rogue base stations within their coverage areas, employing network monitoring and anomaly detection tools. 3) Implement device-level monitoring to detect unexpected modem crashes or connectivity issues that may indicate exploitation attempts. 4) For critical infrastructure and enterprise environments, consider deploying mobile threat defense solutions that can identify suspicious network behavior. 5) Educate users about the risks of connecting to untrusted networks and encourage the use of VPNs or secure communication channels where feasible. 6) Engage with device manufacturers and service providers to verify patch deployment status and request updates if necessary. 7) Maintain incident response plans that include scenarios involving mobile device denial of service to minimize operational impact.