CVE-2025-20750 is a vulnerability classified under CWE-476 (NULL Pointer Dereference) found in MediaTek modem chipsets including MT2735, MT6833 series, MT6853 series, MT6873 series, MT6880 series, MT6890 series, MT8675, MT8771, MT8791 series, and MT8797. The flaw arises from improper input validation in the modem firmware (version NR15), which can cause the system to dereference a NULL pointer leading to a crash. This crash results in a denial of service condition on the modem, disrupting network connectivity. The attack vector requires the UE to connect to a rogue base station controlled by an attacker, which can send malformed inputs triggering the vulnerability. No additional privileges or user interaction are necessary, making exploitation feasible in environments where attackers can deploy or simulate base stations. The CVSS v3.1 score is 5.3 (medium), reflecting network attack vector, high attack complexity, low privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high impact on availability. MediaTek has assigned patch ID MOLY01661199 to resolve the issue. While no exploits have been observed in the wild, the vulnerability poses a risk to device stability and service continuity, especially in critical communication scenarios.

For European organizations, the primary impact is a potential denial of service on devices using affected MediaTek modems, which could disrupt mobile communications and IoT operations relying on these chipsets. This could affect sectors such as telecommunications providers, critical infrastructure, transportation, and enterprises using mobile broadband or embedded cellular devices. The disruption caused by modem crashes could lead to loss of connectivity, impacting operational continuity and potentially safety-critical systems. Since exploitation requires proximity to the victim device to operate a rogue base station, the threat is more pronounced in urban or high-value target environments where attackers might deploy such infrastructure. The lack of confidentiality or integrity impact reduces risks of data breaches but availability degradation can still have significant operational consequences. Organizations relying on mobile networks with MediaTek modems should assess their exposure and update devices promptly to maintain service reliability.

1. Apply the official MediaTek patch MOLY01661199 as soon as it becomes available and is integrated into device firmware updates. 2. Network operators and device manufacturers should prioritize rolling out firmware updates to all affected devices, especially those deployed in critical infrastructure or enterprise environments. 3. Implement network monitoring to detect and alert on the presence of rogue base stations or suspicious base station behavior within organizational premises or sensitive areas. 4. Employ baseband firewall or modem security features where available to restrict connections to trusted base stations only. 5. Educate security teams and mobile users about the risks of connecting to unknown or untrusted cellular networks, particularly in high-risk locations. 6. For IoT deployments, consider device management solutions that can enforce firmware updates and monitor device connectivity status to detect anomalies indicative of modem crashes. 7. Collaborate with telecom providers to ensure network-level protections against rogue base stations are in place and effective.