CVE-2026-78796 in B11 Enterprise-level full Gigabit
Summary
by MITRE • 10/09/2026
An issue in Netcore B11 Enterprise-level full Gigabit 9-port shop wireless router v1.3.241114.024540 and before allows a remote attacker to execute arbitrary code via the www\cgi-bin\upgrade file
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Analysis
by VulDB Data Team • 10/09/2026
The vulnerability identified in Netcore B11 Enterprise-level full Gigabit 9-port shop wireless router versions v1.3.241114.024540 and prior represents a critical remote code execution flaw rooted in the device's firmware update mechanism. This specific weakness is located within the web-based management interface, specifically targeting the file path www\cgi-bin\upgrade. The architecture of many consumer-grade routers relies on CGI scripts to handle administrative tasks such as configuration changes and system updates. In this instance, the upgrade functionality fails to adequately sanitize or validate user-supplied input before processing it through underlying system commands. This lack of rigorous validation allows a remote attacker who can access the router's web interface to inject malicious payloads directly into the update process. The severity is compounded by the fact that these routers are often deployed in small business environments where network security hygiene may be less stringent than in enterprise settings, making them attractive targets for initial compromise within a broader attack chain.
From a technical perspective, this flaw aligns with CWE-94 Improper Control of Generation of Code or Command, commonly known as command injection. The vulnerability arises because the upgrade script likely executes system-level commands to unpack and install firmware files without verifying that the uploaded file is legitimate or properly formatted. An attacker can exploit this by crafting a specially designed HTTP request containing malicious code disguised within the upload parameters. When the router processes this request, it inadvertently executes the injected commands with the privileges of the web server process, which often runs as root on embedded Linux systems used in such devices. This privilege escalation allows the attacker to gain full control over the device's operating system, effectively turning the router into a foothold for further network infiltration. The specific path www\cgi-bin\upgrade indicates that the vulnerability is accessible via standard HTTP methods, requiring only authentication credentials if they are known or weak, which is common in default configurations of such hardware.
The operational impact of this vulnerability extends far beyond the compromise of a single device. Once an attacker achieves remote code execution on the router, they can manipulate network traffic to perform man-in-the-middle attacks, intercept sensitive data such as login credentials and financial information, or redirect users to malicious phishing sites. Furthermore, compromised routers are frequently recruited into botnets like Mirai for distributed denial-of-service attacks against other internet infrastructure. The persistence of this vulnerability in older firmware versions highlights the challenge vendors face in maintaining long-term security support for embedded devices. Organizations relying on these routers may find themselves exposed to significant risk if they do not actively monitor for and apply vendor-provided patches, as the attack vector is straightforward and does not require complex exploitation techniques beyond basic web interaction capabilities.
Mitigation strategies must prioritize immediate patching of all affected Netcore B11 units to version v1.3.241114.024541 or later where this flaw has been addressed through improved input validation and stricter access controls on the upgrade endpoint. In environments where updating is not immediately feasible, network segmentation should be implemented to isolate router management interfaces from general user traffic, ensuring that only authorized administrative workstations can interact with the device's web interface. Additionally, enforcing strong, unique passwords for all administrator accounts reduces the likelihood of an attacker gaining the initial access required to exploit this command injection flaw. Security teams should also monitor network logs for unusual outbound connections or abnormal HTTP requests directed at router management interfaces, which may indicate active exploitation attempts. Long-term resilience requires evaluating whether these devices meet current security standards and considering replacement with hardware that offers robust lifecycle support and transparent vulnerability disclosure policies aligned with industry best practices such as those outlined in the MITRE ATT&CK framework under techniques for initial access and execution via web services.