CVE-2026-3399 identifies a buffer overflow vulnerability in the Tenda F453 router firmware version 1.0.0.3. The vulnerability resides in the fromGstDhcpSetSer function within the httpd component, specifically in the processing of the 'dips' argument passed to the /goform/GstDhcpSetSer endpoint. Improper validation or bounds checking of this argument allows an attacker to overflow a buffer, potentially overwriting adjacent memory. This can lead to arbitrary code execution or denial of service on the device. The vulnerability is remotely exploitable without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The CVSS score of 8.7 (high severity) reflects the critical impact on confidentiality, integrity, and availability, with a low attack complexity and no user interaction needed. While no active exploitation has been reported, a public exploit exists, increasing the likelihood of future attacks. The affected product is a widely used consumer and small office router, making this vulnerability a significant risk for network security. The lack of available patches at the time of reporting necessitates immediate mitigation efforts to reduce exposure.

The exploitation of this buffer overflow vulnerability can have severe consequences for organizations using the Tenda F453 router. Attackers can gain unauthorized remote code execution capabilities, allowing them to take full control of the device. This can lead to interception or manipulation of network traffic, insertion of malicious payloads, lateral movement within internal networks, and disruption of network availability. Confidential data passing through the router may be compromised, and the integrity of network communications can be undermined. The availability of the router can also be affected, resulting in denial of service conditions. Given the router’s role as a network gateway, successful exploitation can serve as a foothold for broader network compromise. Organizations relying on this device for critical connectivity or security functions face increased risk of operational disruption and data breaches.

1. Immediate firmware update: Organizations should monitor Tenda’s official channels for a security patch addressing CVE-2026-3399 and apply it as soon as it becomes available. 2. Network segmentation: Isolate vulnerable Tenda F453 devices from critical network segments to limit potential lateral movement if compromised. 3. Access control: Restrict remote management access to the router’s administrative interfaces, ideally limiting access to trusted IP addresses or disabling remote management entirely. 4. Intrusion detection: Deploy network monitoring and intrusion detection systems to identify unusual traffic patterns or exploit attempts targeting the /goform/GstDhcpSetSer endpoint. 5. Temporary workaround: If patching is not immediately possible, consider disabling or filtering HTTP requests to the vulnerable endpoint at the network perimeter or firewall level. 6. Device replacement: For environments where security is paramount and patching is delayed, consider replacing affected devices with models from vendors with timely security support. 7. Regular audits: Conduct periodic security assessments of network devices to detect unpatched vulnerabilities and unauthorized configuration changes.