CVE-2026-2907 identifies a critical stack-based buffer overflow vulnerability in the Tenda HG9 router, firmware version 300001138. The flaw exists in the GPON Configuration Endpoint, specifically within the /boaform/formgponConf interface, which processes the parameters fmgpon_loid and fmgpon_loid_password. Improper validation or sanitization of these inputs allows an attacker to overflow the stack buffer remotely, potentially overwriting return addresses or control data. This vulnerability does not require user interaction and can be exploited over the network without prior authentication, making it highly accessible to attackers. Successful exploitation can lead to arbitrary code execution on the device, enabling attackers to take full control of the router, disrupt network traffic, intercept sensitive data, or pivot to internal networks. The CVSS v4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges. Although no active exploitation in the wild has been reported, the availability of a public exploit increases the likelihood of future attacks. The vulnerability affects a critical network device component, making it a significant threat to organizations relying on Tenda HG9 routers for internet connectivity and GPON services.

The impact of CVE-2026-2907 is substantial for organizations using Tenda HG9 routers, particularly in environments where these devices serve as primary gateways or GPON endpoints. Exploitation can lead to full device compromise, allowing attackers to intercept or manipulate network traffic, disrupt internet connectivity, or use the compromised router as a foothold for lateral movement within internal networks. This can result in data breaches, service outages, and loss of trust in network infrastructure. Given the router's role in residential and small-to-medium business networks, the vulnerability could affect a broad user base, potentially impacting critical communications and services. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the risk of automated or mass exploitation campaigns. Organizations may face regulatory and compliance repercussions if sensitive data is exposed due to this vulnerability. Additionally, compromised routers could be enlisted in botnets or used to launch further attacks, amplifying the threat landscape.

To mitigate CVE-2026-2907, organizations should immediately verify if their Tenda HG9 routers are running the affected firmware version 300001138 and prioritize upgrading to a patched firmware once available from the vendor. In the absence of an official patch, network administrators should implement compensating controls such as restricting access to the router's management interfaces via firewall rules, limiting exposure to trusted IP addresses only. Disabling remote management features, especially those related to GPON configuration endpoints, can reduce attack surface. Network segmentation should be enforced to isolate vulnerable devices from critical infrastructure. Continuous monitoring for unusual traffic patterns or exploitation attempts targeting /boaform/formgponConf is advised. Employing intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability can help detect and block exploit attempts. Regularly auditing device configurations and maintaining an inventory of network hardware will aid in rapid response. Finally, educating users and administrators about the risks and signs of compromise can enhance overall security posture.