CVE-2026-76008 in CF-N1-S
Summary
by MITRE • 08/19/2026
A flaw has been found in Comfast CF-N1-S 2.6.0.1. This affects the function get_para_from_uri of the file /cgi-bin/mbox-config of the component URI Parameter Parsing. This manipulation of the argument width/height causes stack-based buffer overflow. The attack can be initiated remotely.
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Analysis
by VulDB Data Team • 08/19/2026
The vulnerability identified in Comfast CF-N1-S firmware version 2.6.0.1 represents a critical security flaw within the device's web management interface, specifically targeting the URI parameter parsing logic. This component is responsible for processing input data sent via HTTP requests to configure various network settings and operational parameters of the router or wireless access point. The specific function affected is get_para_from_uri located in the CGI script file /cgi-bin/mbox-config. This script serves as a bridge between the user-facing web interface and the underlying system configuration, making it a high-value target for attackers seeking to gain unauthorized control over network infrastructure.
The technical nature of this vulnerability is a stack-based buffer overflow caused by improper validation of input arguments, particularly those related to width and height parameters. When the get_para_from_uri function processes these values, it fails to adequately check the length or format of the data before copying it into a fixed-size memory buffer on the call stack. This lack of bounds checking allows an attacker to supply oversized or malformed strings that exceed the allocated memory space. As a result, excess data overwrites adjacent memory locations, potentially corrupting critical control structures such as return addresses and saved frame pointers.
From an operational perspective, this flaw enables remote code execution without requiring any form of authentication on many default configurations, although some implementations may require prior login depending on specific deployment settings. An attacker can exploit this vulnerability by crafting a malicious HTTP request with specially crafted width or height parameters that trigger the buffer overflow condition. Successful exploitation allows the injection and execution of arbitrary shell commands on the device's operating system. This effectively grants the attacker full administrative control over the compromised hardware, turning it into a node within a botnet or allowing for further lateral movement within the local network segment.
The impact extends beyond simple remote code execution to include significant risks to data confidentiality and integrity. Compromised devices can be used to intercept unencrypted traffic, perform man-in-the-middle attacks against other users on the same network, or serve as launchpads for distributed denial-of-service attacks against external targets. Furthermore, because these devices often manage Wi-Fi credentials and gateway settings, their compromise poses a direct threat to the privacy of all connected clients. The ability to execute code remotely makes this vulnerability particularly dangerous in environments where physical access is restricted but network connectivity is available.
This flaw aligns with Common Weakness Enumeration identifier CWE-120, which describes buffer copy without checking size limits, and more specifically relates to stack-based buffer overflow scenarios often categorized under CWE-787 or associated memory corruption weaknesses. In the context of the MITRE ATT&CK framework for IoT devices, this vulnerability facilitates initial access through exploitation of remote services (T1190) and enables privilege escalation if lower-level user accounts are targeted first. The attack vector is classified as network-based with low complexity due to the automated nature of buffer overflow exploits against poorly validated CGI scripts.
Mitigation strategies should prioritize immediate firmware updates provided by Comfast that address this specific input validation failure in the mbox-config script. If an update is not yet available, administrators can implement temporary mitigations such as restricting access to the web management interface via firewall rules or VLAN segmentation to limit exposure to untrusted networks. Additionally, deploying intrusion detection systems capable of identifying anomalous HTTP request patterns with oversized parameters may help detect and block exploitation attempts in real-time. Long-term remediation requires developers to enforce strict input sanitization routines that validate parameter lengths against expected maximums before processing them within the application logic.