CVE-2026-2905 is a stack-based buffer overflow vulnerability identified in the Tenda HG9 router firmware version 300001138. The flaw exists in the Wireless Configuration Endpoint, specifically in the /boaform/formWlanSetup component, where the 'ssid' parameter is improperly validated. An attacker can remotely send a specially crafted request manipulating the 'ssid' argument, causing a stack overflow. This overflow can overwrite critical memory regions, potentially allowing arbitrary code execution with elevated privileges on the device. The vulnerability requires no authentication or user interaction, making it highly exploitable over the network. The CVSS 4.0 base score of 8.7 reflects its high severity, with low attack complexity and no privileges required. Although no official patch has been released, a public exploit is available, increasing the threat level. Exploiting this vulnerability could allow attackers to take full control of affected devices, disrupt wireless network availability, or use the compromised router as a foothold for further attacks within the network. The vulnerability affects a widely deployed consumer-grade router, increasing the potential attack surface globally.

The impact of CVE-2026-2905 is significant for organizations using Tenda HG9 routers, as exploitation can lead to full device compromise. Attackers gaining control over the router can intercept, modify, or block network traffic, undermining confidentiality and integrity. They may also disrupt network availability by causing device crashes or reboots. Compromised routers can serve as entry points for lateral movement within corporate or home networks, facilitating further attacks such as data exfiltration or malware deployment. Given the router’s role in wireless connectivity, the vulnerability could affect both enterprise and residential environments, potentially impacting critical business operations and personal data security. The availability of a public exploit increases the likelihood of active exploitation, raising the urgency for mitigation. The lack of an official patch means affected organizations must rely on interim controls to reduce risk.

1. Immediately disable remote management interfaces on Tenda HG9 devices to prevent external exploitation. 2. Restrict network access to the router’s management interface by implementing strict firewall rules and network segmentation, isolating the device from untrusted networks. 3. Monitor network traffic for unusual patterns or attempts to access /boaform/formWlanSetup with suspicious 'ssid' parameters. 4. Use intrusion detection/prevention systems (IDS/IPS) with signatures targeting this specific exploit once available. 5. Regularly audit and update router firmware; although no patch is currently available, monitor Tenda’s official channels for updates and apply patches promptly upon release. 6. Consider replacing affected devices with models from vendors with a stronger security track record if mitigation is not feasible. 7. Educate network administrators about this vulnerability and enforce strict configuration management to avoid exposure. 8. Implement network-level anomaly detection to identify potential exploitation attempts early.