CVE-2026-3970 in Tenda
Summary
by MITRE • 03/12/2026
A flaw has been found in Tenda i3 1.0.0.6(2204). Affected is the function formwrlSSIDget of the file /goform/wifiSSIDget. Executing a manipulation of the argument index can lead to stack-based buffer overflow. The attack may be launched remotely. The exploit has been published and may be used.
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Analysis
by VulDB Data Team • 03/17/2026
The vulnerability identified as CVE-2026-3970 represents a critical stack-based buffer overflow flaw within the Tenda i3 router firmware version 1.0.0.6(2204). This vulnerability resides in the formwrlSSIDget function located within the /goform/wifiSSIDget file, which serves as a web interface component for managing wireless network settings. The flaw emerges from insufficient input validation when processing the index argument, creating a pathway for malicious actors to manipulate memory layout and potentially execute arbitrary code. The affected device operates under a web-based management interface that exposes this vulnerable function to remote exploitation, making it particularly dangerous as it does not require physical access or local network privileges to exploit. The vulnerability's classification aligns with CWE-121 Stack-based Buffer Overflow, which occurs when data written to a stack buffer exceeds the buffer's allocated size, leading to memory corruption and potential privilege escalation.
The technical exploitation of this vulnerability involves crafting a malicious request to the /goform/wifiSSIDget endpoint with a manipulated index parameter that exceeds the buffer's capacity. This overflow can overwrite adjacent memory locations including return addresses, function pointers, and other critical program state information. The remote attack vector means that an unauthenticated attacker can initiate the exploit from outside the network perimeter, potentially compromising the entire router and its connected network. The published exploit demonstrates that attackers can leverage this flaw to gain unauthorized access to the device's administrative interface, potentially leading to complete network takeover. This vulnerability represents a significant risk to enterprise and home network security as routers often serve as the primary gateway and control point for network traffic, making them attractive targets for attackers seeking persistent access to larger network infrastructures.
The operational impact of CVE-2026-3970 extends beyond simple device compromise, as it can enable attackers to establish persistent backdoors, monitor network traffic, redirect DNS requests, and potentially use the compromised device as a launching point for attacks against other networked systems. The vulnerability's presence in a widely deployed router model means that numerous devices could be simultaneously compromised, creating a potential attack surface that spans multiple organizations and geographical locations. Network administrators may face challenges in identifying affected devices due to the remote nature of the vulnerability, and the lack of proper input validation makes detection difficult through conventional network monitoring approaches. The exploitation of this flaw could also facilitate advanced persistent threat campaigns where attackers maintain long-term access to network resources, potentially exfiltrating sensitive data or establishing command and control infrastructure.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from Tenda, as the manufacturer is likely to release patches addressing the buffer overflow issue through proper input validation and bounds checking. Network segmentation and firewall rules should be implemented to restrict access to the router's web management interface from untrusted networks, while also monitoring for unusual traffic patterns that might indicate exploitation attempts. The implementation of network intrusion detection systems can help identify exploitation attempts by monitoring for specific payload patterns associated with buffer overflow attacks. Additionally, organizations should conduct comprehensive vulnerability assessments to identify all instances of the affected Tenda i3 router models within their network infrastructure and ensure proper network access controls are in place. The ATT&CK framework categorizes this vulnerability under T1210 Exploitation for Credential Access and T1071.004 Application Layer Protocol DNS, as attackers could potentially use compromised routers to harvest credentials or redirect network traffic. Regular security audits and network monitoring should be enhanced to detect unauthorized access attempts, while the principle of least privilege should be applied to restrict administrative access to network devices.