CVE-2026-3273 identifies a critical buffer overflow vulnerability in the Tenda F453 router firmware version 1.0.0.3. The flaw resides in the formWrlsafeset function of the httpd component, specifically in the handling of the mit_ssid_index parameter within the /goform/AdvSetWrlsafeset endpoint. An attacker can remotely send crafted requests manipulating this argument to overflow a buffer, potentially overwriting memory and enabling arbitrary code execution or causing a denial of service. The vulnerability requires no authentication or user interaction, making it exploitable by any remote attacker with network access to the device. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with ease of exploitation. Although no known exploits in the wild have been reported, public exploit code availability increases the likelihood of attacks. The vulnerability affects a widely deployed consumer and small office router model, which is often used as a network gateway, amplifying the potential impact. No official patches have been linked yet, so mitigation relies on network-level controls and disabling vulnerable services where possible.

The vulnerability allows remote attackers to execute arbitrary code or cause denial of service on affected Tenda F453 routers, compromising the confidentiality, integrity, and availability of network traffic passing through these devices. Exploitation could lead to full device takeover, enabling attackers to intercept, modify, or disrupt network communications, launch further attacks within the internal network, or use the device as a foothold for persistent access. This poses a significant risk to home users, small businesses, and organizations relying on these routers for secure internet connectivity. The lack of authentication and user interaction requirements increases the attack surface and potential for widespread exploitation. Network outages, data breaches, and unauthorized access to internal resources are plausible consequences, impacting operational continuity and data security.

1. Immediately isolate affected Tenda F453 devices from untrusted networks to prevent remote exploitation. 2. Monitor vendor communications for official firmware updates or patches addressing CVE-2026-3273 and apply them promptly once available. 3. If patches are unavailable, consider replacing vulnerable devices with models from vendors with active security support. 4. Implement network-level protections such as firewall rules to restrict access to the /goform/AdvSetWrlsafeset endpoint or block management interfaces from external networks. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting exploit attempts against this vulnerability. 6. Regularly audit network devices for firmware versions and known vulnerabilities to maintain an accurate asset inventory. 7. Educate users and administrators about the risks of exposed router management interfaces and enforce strong network segmentation to limit exposure. 8. Disable remote management features if not required to reduce attack vectors.