CVE-2026-3275 is a buffer overflow vulnerability identified in the Tenda F453 router firmware version 1.0.0.3. The vulnerability resides in the fromAddressNat function within the httpd service, which processes requests to the /goform/addressNat endpoint. Specifically, the vulnerability arises from improper handling of the 'entrys' argument, allowing an attacker to overflow a buffer by sending crafted input. This flaw can be exploited remotely over the network without requiring authentication or user interaction, making it highly accessible to attackers. The buffer overflow could enable an attacker to execute arbitrary code on the device, potentially gaining full control over the router, or cause a denial of service by crashing the service. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges. Although no active exploitation in the wild has been reported, a public exploit is available, increasing the urgency for mitigation. The vulnerability affects a widely used consumer and small business router model, which may be deployed in various organizational environments, including home offices and small enterprises. The lack of available patches at the time of disclosure necessitates immediate risk management and mitigation strategies to prevent exploitation.

The exploitation of CVE-2026-3275 could have severe consequences for organizations worldwide. Successful attacks may allow adversaries to execute arbitrary code remotely on affected Tenda F453 routers, leading to full device compromise. This could enable attackers to intercept or manipulate network traffic, pivot to internal networks, or establish persistent backdoors. The confidentiality of sensitive data traversing the network could be breached, while integrity and availability of network services may be disrupted through denial-of-service conditions. Small businesses and home offices relying on these routers for internet connectivity and network segmentation are particularly vulnerable, as compromised devices can serve as entry points for broader network intrusions. The public availability of exploits increases the likelihood of opportunistic attacks, including automated scanning and exploitation by malware. The absence of patches at disclosure heightens the risk window, potentially affecting thousands of devices globally. Organizations may face operational disruptions, data breaches, and reputational damage if this vulnerability is exploited.

To mitigate CVE-2026-3275, organizations should first verify if they are using Tenda F453 routers running firmware version 1.0.0.3. Immediate steps include isolating affected devices from untrusted networks and restricting access to the /goform/addressNat endpoint via firewall rules or network segmentation. Network administrators should monitor router logs and network traffic for unusual activity indicative of exploitation attempts. If vendor patches or firmware updates become available, they must be applied promptly. In the absence of official patches, consider deploying intrusion prevention systems (IPS) with signatures targeting this vulnerability or blocking suspicious payloads targeting the 'entrys' parameter. Additionally, disabling remote management features and restricting administrative access to trusted networks can reduce exposure. Regularly updating router firmware and maintaining an inventory of network devices will aid in rapid response to similar vulnerabilities. Organizations should also educate users about the risks of using outdated networking equipment and consider upgrading to more secure models if feasible.