CVE-2025-20678 is a vulnerability classified under CWE-674 (Uncontrolled Recursion) found in the IMS service of multiple MediaTek modem chipsets, including but not limited to MT6739, MT6761, MT6762 series, MT6769 series, and many others. The flaw arises due to improper error handling within the IMS service, which leads to uncontrolled recursion and ultimately causes a system crash. This crash results in a denial of service condition on the affected device. The vulnerability can be triggered remotely without any user interaction or elevated privileges, provided the device connects to a rogue base station controlled by an attacker. The affected modem firmware versions include LR12A, LR13, NR15, NR16, NR17, and NR17R. The CVSS v3.1 score is 6.5 (medium severity), reflecting the ease of remote exploitation (attack vector: adjacent network), no required privileges or user interaction, and impact limited to availability (no confidentiality or integrity impact). The vulnerability is significant because it targets the IMS service, a critical component for voice and multimedia services over LTE and 5G networks. Disruption of IMS can degrade or halt telephony and data services on affected devices. Although no known exploits are currently reported in the wild, the broad range of affected chipsets and firmware versions indicates a large attack surface. MediaTek has assigned patch ID MOLY01394606 to address this issue, emphasizing the need for timely firmware updates.

For European organizations, the primary impact of CVE-2025-20678 is the potential for remote denial of service on devices using affected MediaTek chipsets. This can disrupt mobile communications, including voice, SMS, and data services reliant on IMS, impacting both consumer and enterprise users. Telecommunications providers, emergency services, and critical infrastructure operators using devices with these chipsets could experience service outages or degraded network reliability. The vulnerability could be exploited by attackers deploying rogue base stations, which may be feasible in urban or high-value target areas. Disruption of mobile services can affect business continuity, emergency response, and operational communications. Additionally, enterprises with BYOD policies or mobile workforce relying on vulnerable devices may face increased risk of communication downtime. The lack of required user interaction or privileges lowers the barrier for exploitation, increasing the threat level in environments where rogue base stations can be deployed or encountered. However, the impact is limited to availability, with no direct compromise of data confidentiality or integrity.

1. Immediate deployment of the official patch MOLY01394606 from MediaTek or device manufacturers incorporating this fix is critical. 2. Network operators should monitor for and mitigate rogue base stations using IMSI catchers or similar detection technologies to reduce exposure to attack vectors. 3. Enterprises should inventory devices to identify those with affected MediaTek chipsets and firmware versions and prioritize updates or device replacements. 4. Implement network-level anomaly detection to identify unusual IMS service disruptions or signaling patterns indicative of exploitation attempts. 5. Encourage users to avoid connecting to untrusted or unknown cellular networks, especially in sensitive or high-risk locations. 6. Collaborate with mobile network providers to ensure rapid dissemination of patches and security advisories. 7. For critical infrastructure, consider deploying multi-factor communication channels to maintain operational continuity if mobile services are disrupted. 8. Regularly update device firmware and baseband software as part of a comprehensive mobile device management strategy.