CVE-2026-4551 is a stack-based buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability exists in the fromSafeClientFilter function of the /goform/SafeClientFilter component, specifically triggered by manipulation of the 'menufacturer/Go' argument. This improper input validation leads to a stack buffer overflow, which can be exploited remotely without requiring authentication or user interaction. The overflow can corrupt the stack, potentially allowing an attacker to execute arbitrary code with the privileges of the affected process or cause a denial of service by crashing the device. The vulnerability is significant because it affects the router's parameter handling mechanism, a critical component for device configuration and operation. The CVSS 4.0 base score is 8.7, indicating high severity due to network attack vector, low attack complexity, no privileges required, and no user interaction needed. The vulnerability has been publicly disclosed, and proof-of-concept exploit code is available, although no confirmed exploitation in the wild has been reported. The Tenda F453 is a consumer-grade router commonly used in home and small office environments, making this vulnerability a concern for a broad user base. The lack of available patches at the time of disclosure increases the urgency for mitigation. This vulnerability highlights the importance of robust input validation in embedded device firmware to prevent memory corruption issues.

The impact of CVE-2026-4551 is substantial for organizations and individuals using the Tenda F453 router. Successful exploitation can lead to arbitrary code execution, allowing attackers to take full control of the device, manipulate network traffic, or pivot to internal networks. This compromises confidentiality, as sensitive data passing through the router could be intercepted or altered. Integrity is at risk due to potential unauthorized changes to device configuration or network traffic. Availability may be affected if the device is crashed or rendered inoperable through denial of service. Given the router's role as a network gateway, exploitation could facilitate broader network compromise, including lateral movement to connected systems. The vulnerability's remote and unauthenticated nature significantly increases the attack surface, enabling attackers to target devices over the internet or local network without prior access. This poses a risk to home users, small businesses, and potentially larger organizations relying on these devices for network connectivity. The public availability of exploit code raises the likelihood of attacks, especially from opportunistic threat actors. Without timely patching or mitigation, affected devices remain vulnerable to compromise, data breaches, and network disruption.

To mitigate CVE-2026-4551, organizations and users should take immediate steps beyond generic advice: 1) Check for and apply any official firmware updates from Tenda addressing this vulnerability; if no patch is available, consider upgrading to a newer, unaffected device model. 2) Restrict remote management access to the router by disabling WAN-side administration and limiting access to trusted IP addresses only. 3) Implement network segmentation to isolate the router management interface from critical internal networks. 4) Monitor network traffic for unusual activity or signs of exploitation attempts targeting the /goform/SafeClientFilter endpoint. 5) Use network intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability or anomalous HTTP requests to the vulnerable endpoint. 6) If possible, disable or restrict the vulnerable functionality related to the fromSafeClientFilter component until a patch is applied. 7) Educate users about the risks of using outdated firmware and the importance of timely updates. 8) Consider deploying additional security controls such as endpoint protection and network firewalls to detect and block exploitation attempts. These targeted measures help reduce exposure and limit the potential impact while awaiting official remediation.