CVE-2026-7192 in T-CPE301K Mini WiFi Router
Summary
by MITRE • 09/29/2026
A stack-based buffer overflow vulnerability in the Dbit T-CPE301K 4G WiFi minirouter allows an authenticated attacker to cause a denial of service (DoS) and a system reboot via a manipulated HTTP POST request directed at the endpoint ‘/js/common/do_cmd.js’ endpoint containing an excessively long parameter, which overwrites the PC and RA registers.
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified in the Dbit T-CPE301K 4G WiFi minirouter represents a critical stack-based buffer overflow condition located within the device's web management interface. This flaw is specifically triggered when processing HTTP POST requests directed at the JavaScript endpoint /js/common/do_cmd.js. The root cause lies in insufficient validation of input data length before it is copied into a fixed-size buffer on the application stack. When an attacker submits a parameter with excessive length, the copy operation exceeds the allocated memory boundaries, leading to corruption of adjacent stack frames and critical processor registers such as the Program Counter (PC) and Return Address (RA). This type of flaw is classically categorized under CWE-121: Stack-based Buffer Overflow, which remains one of the most prevalent and dangerous classes of software vulnerabilities due to its potential for arbitrary code execution.
Although the vulnerability requires authentication to exploit, this does not eliminate the severity of the risk in many operational contexts. In typical home or small office deployments, administrative credentials are often weak, default, or shared among multiple users, making them susceptible to credential theft via phishing, brute force attacks, or physical access. Furthermore, if the device is exposed to a network where authenticated sessions can be hijacked through session fixation or cross-site request forgery techniques, an attacker could leverage this overflow without direct knowledge of the password. The exploitation path aligns with MITRE ATT&CK technique T1059: Command and Scripting Interpreter, as the ability to overwrite return addresses allows for control over program flow, potentially leading to remote code execution or persistent backdoor installation if the device is part of a larger compromised network infrastructure.
The immediate operational impact of this vulnerability is a denial of service resulting in an automatic system reboot. The corruption of the PC and RA registers causes the microcontroller or processor within the router to jump to an invalid memory address, triggering a hardware exception that forces a hard reset. This results in complete loss of connectivity for all devices relying on the minirouter for internet access. While the primary observed effect is availability disruption, the underlying mechanism poses a far greater threat than simple downtime. Stack-based buffer overflows are frequently precursors to more severe compromises where an attacker crafts specific payload data to overwrite function pointers or shellcode injection vectors, thereby gaining full control over the embedded device. This could allow for network pivoting, interception of unencrypted traffic, or use of the compromised router as a launchpad for attacks against internal assets.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The most effective solution is to apply firmware updates provided by Dbit that patch this buffer overflow issue through proper input sanitization and bounds checking mechanisms such as stack canaries or Address Space Layout Randomization if supported by the hardware architecture. In cases where patches are unavailable, administrators should restrict access to the web management interface by disabling remote administration features and ensuring it is only accessible from trusted local network segments. Implementing strong, unique administrative passwords reduces the likelihood of an attacker obtaining the necessary authentication credentials. Additionally, enabling logging on connected firewalls or intrusion detection systems can help identify attempts to send abnormally large POST requests to this endpoint, allowing for proactive blocking before exploitation occurs. Regular security audits and adherence to secure coding standards like those outlined in OWASP guidelines for embedded devices are essential to prevent similar vulnerabilities in future firmware releases.