CVE-2026-3700 identifies a critical buffer overflow vulnerability in the UTT HiPER 810G device firmware versions up to 1.7.7-171114. The vulnerability arises from improper handling of input in the strcpy function located in the /goform/formConfigDnsFilterGlobal endpoint. This function copies user-supplied data without bounds checking, enabling an attacker to overflow the buffer remotely. The flaw does not require authentication or user interaction, making it highly exploitable over the network. Successful exploitation can lead to arbitrary code execution, allowing attackers to gain control over the device, disrupt services, or exfiltrate sensitive information. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P) indicates network attack vector, low complexity, no authentication, no user interaction, and high impact on confidentiality, integrity, and availability. Although no active exploitation has been reported, a public exploit code is available, increasing the likelihood of future attacks. The vulnerability affects a widely used network device, often deployed in enterprise and industrial environments, making it a significant security concern.

The impact of CVE-2026-3700 is substantial for organizations relying on UTT HiPER 810G devices. Exploitation can lead to full compromise of affected devices, including unauthorized access, data leakage, service disruption, and potential lateral movement within networks. Given the device's role in network infrastructure, attackers could manipulate DNS filtering configurations, degrade network security, or cause denial of service. This could affect operational continuity, data confidentiality, and integrity, particularly in environments where these devices are integral to network management or security enforcement. The availability of a public exploit increases the risk of widespread attacks, potentially targeting critical infrastructure sectors, enterprises, and service providers. The vulnerability's remote exploitability without authentication further exacerbates its threat level, making it a prime target for attackers seeking to gain footholds in networks.

To mitigate CVE-2026-3700, organizations should immediately verify if they are running affected versions of UTT HiPER 810G firmware (up to 1.7.7-171114) and apply any available vendor patches or firmware updates once released. In the absence of patches, network-level mitigations should be implemented, such as restricting access to the management interface and the /goform/formConfigDnsFilterGlobal endpoint using firewall rules or network segmentation to limit exposure. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for exploit attempts targeting this vulnerability. Regularly audit device configurations and logs for unusual activity. Additionally, consider deploying web application firewalls (WAF) capable of detecting and blocking buffer overflow attack patterns. Organizations should also maintain an inventory of affected devices and prioritize their remediation based on criticality. Finally, coordinate with UTT support channels for guidance and updates on official patches or workarounds.