Tenda F456 CVE-2026-7057

Exploitation requires the attacker to possess valid low-privilege authentication credentials for the Tenda F456 router's web administration interface, typically the default or user-configured admin username and password. The router must have the httpd web server enabled and accessible over the network (standard default configuration). No special features need to be enabled beyond the base administrative web interface that provides access to the /goform/setcfm configuration endpoint. LIMITING FACTORS: Authentication requirement prevents completely unauthenticated remote exploitation, though this protection is significantly weakened if default credentials remain unchanged (common in consumer routers) or if credentials have been exposed through phishing, credential reuse, or prior compromise. Network accessibility can be limited by disabling remote administration or firewall rules restricting access to the management interface from untrusted networks. The vulnerability affects the core configuration management function, not an optional feature, meaning it cannot be disabled without losing router management capabilities.

Real-world risk is MODERATE to HIGH despite the 7.4 CVSS score, with conflicting signals requiring careful analysis. POSITIVE RISK FACTORS: Publicly available exploit code (GitHub repository documented in references) significantly lowers exploitation barrier, and the CVSS E:P (Proof-of-concept) modifier confirms weaponization. Network attack vector (AV:N) and low complexity (AC:L) enable remote exploitation without specialized conditions. IoT routers are high-value targets for botnet recruitment and network pivoting. MITIGATING FACTORS: Authentication requirement (PR:L) means attackers need valid router admin credentials first, though default/weak credentials are endemic in consumer routers. No CISA KEV listing suggests this is not yet observed in widespread exploitation campaigns. EPSS data not provided, preventing probability assessment. CRITICAL DATA GAP: No vendor security advisory from Tenda identified, and no patched firmware version confirmed in available data - this suggests potential abandonment of this router model. The CVSS Scope:Unchanged (S:X default) may underestimate risk if router compromise enables lateral movement to other network segments. Priority depends heavily on whether default credentials are still in use and whether the F456 model remains deployed in production networks.

An attacker who has obtained or guessed the router's administrative credentials (often default credentials like admin/admin on consumer routers) authenticates to the Tenda F456 web interface over the network. Using the publicly available exploit code from GitHub (https://github.com/Litengzheng/vuldb_new/blob/main/F456/vul_128/README.md), they craft a malicious HTTP POST request to the /goform/setcfm endpoint with oversized funcname or funcpara1 parameter values designed to overflow the httpd process buffer. The overflow overwrites return addresses or function pointers in memory, redirecting execution to attacker-controlled shellcode. With successful exploitation, the attacker gains arbitrary code execution at the privilege level of the httpd process (typically root on embedded devices), enabling full router compromise, persistent backdoor installation, traffic interception, DNS hijacking for the entire network, or recruitment into a botnet.