Tenda F456 EUVD-2026-25704

Exploitation requires authenticated access to the Tenda F456 web management interface (CVSS PR:L - low privilege required). Attacker must successfully authenticate as an administrative user, typically using the router's web UI on port 80/443, before sending malicious requests to the /goform/addressNat endpoint. The vulnerability affects the NAT address configuration feature specifically, accessed through the router's network settings interface. Limiting factors that reduce exploitation likelihood in practice: (1) Management interface should not be accessible from WAN/internet in secure configurations (only LAN access), (2) Strong non-default admin credentials prevent initial authentication, (3) Many residential deployments place routers behind ISP-managed equipment adding network isolation. No special NAT configuration state or feature enablement is required beyond standard router operation - the vulnerable function is part of core NAT management functionality present in default configurations.

Real-world risk is MODERATE-HIGH for exposed management interfaces but LIMITED in typical deployments. The CVSS 4.0 vector (AV:N/AC:L/PR:L) indicates network-exploitable with low complexity but requiring low-privilege authentication - attackers need valid admin credentials first. The E:P (Proof-of-concept) modifier confirms working exploit code exists on GitHub, significantly lowering the skill barrier for attacks. However, exploitation prerequisite is authentication to the router's web interface, which should not be internet-exposed in secure deployments. Risk is ELEVATED for: (1) routers with management interfaces exposed to WAN due to misconfiguration, (2) environments where default/weak admin credentials remain unchanged, (3) lateral movement scenarios where attackers already compromise the local network. The high impact metrics (VC:H/VI:H/VA:H) indicate complete device compromise is possible post-exploitation. CRITICAL MISSING DATA: No EPSS score provided to assess real-world exploitation probability, no CISA KEV status to confirm active campaigns, no vendor security advisory to verify patch status - risk assessment relies primarily on CVSS and POC availability.

An attacker on the local network or internet (if management interface exposed) first authenticates to the Tenda F456 web interface using default credentials (admin/admin) or credentials obtained through phishing. The attacker then sends a crafted HTTP POST request to /goform/addressNat with oversized 'menufacturer' or 'Go' parameter values (based on the public POC at https://github.com/Litengzheng/vuldb_new/blob/main/F456/vul_119/README.md), triggering the buffer overflow in fromaddressNat function. This corrupts stack memory, allowing injection of shellcode to execute arbitrary commands with root privileges, enabling the attacker to install persistent backdoors, intercept network traffic, or pivot to other devices on the network.