CVE-2026-3972 in Tenda
Summary
by MITRE • 03/12/2026
A vulnerability was found in Tenda W3 1.0.0.3(2204). Affected by this issue is the function formSetCfm of the file /goform/setcfm of the component HTTP Handler. The manipulation of the argument funcpara1 results in stack-based buffer overflow. The attack can only be performed from the local network. The exploit has been made public and could be used.
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Analysis
by VulDB Data Team • 03/17/2026
This vulnerability exists within the Tenda W3 router firmware version 1.0.0.3(2204) and specifically targets the HTTP handler component. The affected function formSetCfm located in the /goform/setcfm file demonstrates a critical stack-based buffer overflow flaw that arises from improper input validation of the funcpara1 argument. The vulnerability represents a classic software security weakness that allows attackers to manipulate memory layout through crafted input parameters, potentially leading to arbitrary code execution or system compromise. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is categorized as a fundamental memory corruption issue that has been consistently identified as a high-risk security flaw in network infrastructure devices.
The attack vector for this vulnerability is constrained to local network access, meaning an attacker must already have network connectivity to the affected device to exploit it. This limitation reduces the attack surface compared to remotely exploitable vulnerabilities but does not eliminate the risk entirely, as local network access can be gained through various means including compromised devices, insider threats, or social engineering attacks. The fact that a public exploit has been developed for this vulnerability significantly increases the threat level, as it removes the requirement for advanced exploit development skills and makes the attack accessible to a broader range of threat actors. This aligns with ATT&CK technique T1210 for exploiting known vulnerabilities and T1059 for command and scripting interpreter usage in executing malicious payloads.
The operational impact of this vulnerability extends beyond simple system compromise, as it represents a critical weakness in network infrastructure security that could enable attackers to gain unauthorized control of the router. A successful exploitation could allow threat actors to modify network configurations, redirect traffic, establish backdoors, or use the device as a pivot point for attacking other systems within the local network. The stack-based buffer overflow specifically poses risks of system crashes, denial of service conditions, or more severe exploitation scenarios where attackers could inject and execute malicious code within the router's memory space. Given that routers serve as primary network gateways, the compromise of such devices can have cascading effects on entire network security postures and potentially expose sensitive internal systems to external threats. Organizations should consider this vulnerability as a potential entry point for advanced persistent threats and implement immediate mitigation measures to protect their network infrastructure from exploitation.
The mitigation approach should focus on immediate firmware updates from Tenda to address the identified buffer overflow vulnerability, while also implementing network segmentation and access controls to limit local network access to authorized personnel only. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, and regular security assessments should be conducted to identify similar vulnerabilities in other network infrastructure components. Additionally, implementing network access control lists and disabling unnecessary services on the router can reduce the attack surface and limit potential exploitation scenarios. This vulnerability serves as a reminder of the critical importance of maintaining up-to-date firmware and conducting regular security audits of network infrastructure devices to prevent exploitation of known vulnerabilities.