Tenda F451 Router Hit with Critical Buffer Overflow

The National Vulnerability Database (NVD) has issued an advisory for CVE-2026-6121, highlighting a critical stack-based buffer overflow in the Tenda F451 router, specifically version 1.0.0.7. This vulnerability, boasting a CVSS score of 8.8 (HIGH), resides within the WrlclientSet function of the /goform/WrlclientSet component, which is part of the router’s httpd service.

The flaw is triggered by manipulating the GO argument, leading to a classic buffer overflow scenario. What makes this particularly nasty is the remote attack vector; an unauthenticated attacker could potentially exploit this without direct physical access. The NVD notes that an exploit has already been published, meaning this isn’t just theoretical — it’s actively weaponizable. This type of vulnerability often leads to remote code execution, giving an attacker full control over the affected device.

For those running these devices, this is a serious red flag. Buffer overflows, particularly in network devices like routers, are prime targets for initial access by threat actors. Once a router is compromised, it can be used for anything from network reconnaissance and data exfiltration to establishing persistent backdoors or launching further attacks within a network.