CVE-2026-2911 is a critical buffer overflow vulnerability identified in the Tenda FH451 router series, specifically affecting firmware versions from 1.0.0.0 through 1.0.0.9. The vulnerability arises from improper handling of input data in the /goform/GstDhcpSetSer endpoint, which is part of the router's web management interface. An attacker can remotely send crafted HTTP requests to this endpoint, causing a buffer overflow condition. This flaw does not require authentication or user interaction, making it highly exploitable over the network. The buffer overflow can lead to memory corruption, enabling attackers to execute arbitrary code with elevated privileges or cause a denial of service by crashing the device. The CVSS v4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no need for privileges or user interaction. Although no exploits have been observed in the wild yet, the public disclosure of the vulnerability increases the likelihood of exploitation attempts. The absence of official patches at the time of disclosure necessitates immediate mitigation strategies to protect affected devices. Given the widespread use of Tenda routers in residential and small business environments, this vulnerability poses a significant risk to network security and device stability.

The impact of CVE-2026-2911 is substantial for organizations and individuals using Tenda FH451 routers. Successful exploitation can lead to full compromise of the device, allowing attackers to execute arbitrary code remotely, potentially gaining control over the router’s functions. This can result in interception or manipulation of network traffic, disruption of internet connectivity, and use of the compromised device as a pivot point for further attacks within the network. Confidentiality is at risk as attackers may intercept sensitive data passing through the router. Integrity can be compromised if attackers alter configurations or inject malicious payloads. Availability is threatened due to potential denial of service conditions caused by crashes. For enterprises relying on these routers for critical connectivity, the vulnerability could lead to operational disruptions and data breaches. The lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of automated exploitation attempts. The public disclosure without an available patch further elevates the risk, necessitating urgent defensive measures.

1. Immediately restrict access to the router’s management interface, especially the /goform/GstDhcpSetSer endpoint, by implementing network segmentation and firewall rules to allow only trusted IP addresses. 2. Disable remote management features if not required to reduce exposure. 3. Monitor network traffic for unusual or malformed HTTP requests targeting the vulnerable endpoint to detect potential exploitation attempts. 4. Apply firmware updates from Tenda as soon as they become available to address the vulnerability directly. 5. If patches are not yet released, consider replacing affected devices with models not susceptible to this vulnerability in high-risk environments. 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting this specific vulnerability or exploit patterns. 7. Educate network administrators about the vulnerability and ensure incident response plans include steps for handling potential exploitation. 8. Regularly audit and update router configurations to minimize attack surface and ensure security best practices are followed.