CVE-2025-50398 identifies a buffer overflow vulnerability in the Mercury D196G device firmware version d196gv1-cn-up_2020-01-09_11.21.44. The flaw exists in the function sub_404CAEDC, which processes the fac_password parameter. Buffer overflow vulnerabilities occur when input data exceeds the allocated buffer size, leading to memory corruption. This can allow attackers to overwrite critical memory regions, potentially enabling arbitrary code execution or causing the device to crash, resulting in denial of service. The vulnerability does not currently have a CVSS score or known exploits in the wild, indicating it may be newly discovered or not yet weaponized. The lack of patch links suggests that no official fix has been released, increasing the urgency for defensive measures. The Mercury D196G device is often used in industrial or networked environments, where such a vulnerability could be exploited remotely if the fac_password parameter is accessible over the network. Exploitation likely does not require authentication, given the nature of buffer overflows in input parameters, increasing the attack surface. The vulnerability's impact includes potential compromise of device integrity, confidentiality (if code execution is achieved), and availability due to crashes. Without mitigation, attackers could leverage this flaw to disrupt operations or gain footholds in critical systems.

For European organizations, the vulnerability poses significant risks, particularly for those deploying Mercury D196G devices in critical infrastructure sectors such as energy, manufacturing, or telecommunications. Exploitation could lead to unauthorized control over affected devices, enabling attackers to disrupt services, manipulate data, or pivot into broader network environments. The potential for denial of service could impact operational continuity, causing downtime and financial losses. Confidentiality breaches could occur if attackers execute arbitrary code to extract sensitive information. Given the absence of patches, organizations face increased exposure until mitigations are implemented. The impact is heightened in environments where these devices are integral to safety or operational processes. Additionally, regulatory compliance frameworks in Europe, such as NIS2, emphasize the protection of critical infrastructure, making exploitation of this vulnerability a compliance risk. The lack of known exploits may reduce immediate risk but also means organizations should proactively address the vulnerability before it is weaponized.

Since no official patches or firmware updates are currently available, European organizations should implement network-level mitigations to reduce exposure. These include restricting access to the Mercury D196G devices by implementing strict firewall rules and network segmentation to isolate vulnerable devices from untrusted networks. Input validation or filtering at the network perimeter could help block malicious payloads targeting the fac_password parameter. Monitoring network traffic for anomalous patterns related to this parameter may provide early detection of exploitation attempts. Organizations should engage with the device vendor to obtain timelines for patches or firmware updates and apply them promptly once available. Additionally, conducting vulnerability scans and penetration tests focused on this device can help identify exposure. Maintaining up-to-date asset inventories to track affected devices is critical. Finally, implementing incident response plans tailored to potential device compromise scenarios will improve readiness.