CVE-2026-3769 is a stack-based buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability resides in the WrlclientSet function, specifically in the handling of the GO argument via the /goform/WrlclientSet endpoint. An attacker can remotely send a specially crafted request manipulating the GO parameter to overflow the stack buffer, potentially overwriting the return address or other control data. This can lead to arbitrary code execution on the device with the privileges of the affected process. The vulnerability requires no authentication or user interaction, making it highly exploitable remotely over the network. 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 confirmed exploits in the wild have been reported, a public exploit is available, increasing the urgency for mitigation. The flaw could be leveraged by attackers to gain persistent control over affected routers, enabling interception or manipulation of network traffic, launching further attacks on internal networks, or disrupting network availability.

The impact of CVE-2026-3769 is significant for organizations relying on Tenda F453 routers. Successful exploitation allows remote attackers to execute arbitrary code with elevated privileges, potentially leading to full device compromise. This can result in unauthorized access to internal networks, interception or modification of sensitive data, disruption of network services, and use of compromised devices as pivot points for lateral movement or launching attacks against other targets. The lack of authentication and user interaction requirements increases the risk of widespread exploitation, especially in environments where these routers are exposed to untrusted networks or the internet. Critical infrastructure, small and medium enterprises, and home users using this device are at risk. The availability of a public exploit further raises the likelihood of attacks, potentially leading to data breaches, service outages, and reputational damage.

To mitigate CVE-2026-3769, organizations should immediately check for firmware updates from Tenda addressing this vulnerability and apply them as soon as available. If no patch is currently provided, network administrators should restrict access to the router’s management interfaces by implementing network segmentation and firewall rules to block unauthorized inbound traffic to the /goform/WrlclientSet endpoint. Disabling remote management features or changing default credentials can reduce exposure. Monitoring network traffic for unusual requests targeting the vulnerable endpoint can help detect exploitation attempts. Employing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability can provide additional defense. Organizations should also consider replacing affected devices with more secure alternatives if timely patching is not feasible. Regular security audits and vulnerability assessments of network devices are recommended to identify and remediate similar risks proactively.