CVE-2026-11557: Tenda F451 Stack Buffer Overflow - Remote Code Execution Risk

Technical summary

CVE-2026-11557 is a stack-based buffer overflow (CWE-119, CWE-121) in the fromNatlimit function within the /goform/Natlimit endpoint of Tenda F451's web management interface. The vulnerability stems from insufficient input validation on the 'page' parameter, which can be manipulated to write data beyond allocated stack boundaries. This memory corruption can be leveraged to overwrite return addresses or other critical stack data, enabling code execution or denial of service. The attack vector is network-based and requires low-complexity exploitation with valid authentication credentials (CVSS 3.1 score: 8.8, HIGH severity).

Business impact

Router compromise via this vulnerability could allow attackers to pivot into trusted networks, intercept traffic, modify firmware, or maintain persistent access. For organizations relying on Tenda F451 devices in branch offices, small business deployments, or IoT edge infrastructure, exploitation poses risks to network integrity, data confidentiality, and service availability. The public availability of exploit code accelerates the timeline to weaponized attacks, making rapid patching a business continuity priority.

Affected systems

Tenda F451 firmware versions 1.0.0.7 and 1.0.0.9 are confirmed vulnerable. Organizations should audit their router fleet to identify affected models and firmware revisions. If other firmware versions or related Tenda products are in use, contact Tenda support or consult their advisory for definitive compatibility information.

Exploitability

Exploitation requires network access and valid authentication credentials, which moderates but does not eliminate risk—many router deployments use default or weak credentials, and internal network access is often granted to employee or guest devices. The availability of public exploits means that attack tools are likely already circulating, and threat actors can readily weaponize this vulnerability. No special conditions or user interaction are needed beyond a successful login.

Remediation

Upgrade Tenda F451 to a patched firmware version as provided by Tenda. Verify the exact patch version number and compatibility with your deployment against Tenda's official advisory. In parallel, implement network segmentation to restrict access to the web management interface, enforce strong authentication (unique, complex passwords), and disable remote management if not operationally required. Monitor for suspicious access to /goform/Natlimit endpoints.

Patch guidance

Contact Tenda support or visit their official website to obtain the latest firmware release for the F451 model. Carefully document your current firmware version before upgrading, test in a non-production environment if feasible, and schedule a maintenance window to avoid service disruption. After patching, verify that the device reboots cleanly and that network functions resume normally. Maintain a firmware update log for compliance and incident response purposes.

Detection guidance

Monitor router access logs and web server logs for requests to /goform/Natlimit with unusual or oversized 'page' parameter values. Implement intrusion detection signatures (if available) targeting stack-based buffer overflow patterns in HTTP requests to this endpoint. Flag any authentication attempts from unexpected sources, and correlate with successful logins to identify potential exploitation activity. Review router crash dumps and system logs for memory corruption indicators post-incident.

Why prioritize this

This vulnerability merits immediate attention due to its HIGH CVSS score (8.8), the availability of public exploits, and the router's role as a network perimeter device. Successful exploitation grants internal network access and potential lateral movement capabilities. Organizations should prioritize patching ahead of routine maintenance schedules, particularly for routers in production or business-critical locations.

Risk score, explained

The CVSS 3.1 score of 8.8 reflects the combination of remote network attack capability, low complexity, low privilege requirement, and high impact on confidentiality, integrity, and availability. The score does not account for the aggravating factor of public exploit availability, which further elevates real-world risk. Organizations should treat this as HIGH severity and allocate resources accordingly.

Frequently asked questions