CVE-2026-113391 in Vigor2960
Summary
by MITRE • 10/20/2026
A vulnerability has been found in DrayTek Vigor2960 1.5.1.6 Revision 8218. This affects the function uploadlangs of the file /cgi-bin/mainfunction.cgi of the component Upload Endpoint. Such manipulation leads to command injection. The attack can be executed remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 1.5.1.7 is able to mitigate this issue. It is recommended to upgrade the affected component. The vendor explains: "2960 1.5.1.7 has corrected many security issues. And 2960 is EoS with limited support, only major issues would be reviewed(e.g. unauthenticated vuln.)". This vulnerability only affects products that are no longer supported by the maintainer.
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Analysis
by VulDB Data Team • 10/20/2026
The DrayTek Vigor2960 router, specifically firmware version 1.5.1.6 Revision 8218, contains a critical remote command injection vulnerability within its web management interface. This flaw resides in the uploadlangs function of the mainfunction.cgi script, which serves as an endpoint for uploading language files to configure the device's localization settings. The vulnerability allows an unauthenticated attacker to execute arbitrary system commands on the underlying operating system by manipulating input parameters sent during the file upload process. Because this component is part of the administrative interface accessible over a network, the attack vector is remote and does not require prior authentication, significantly increasing its severity and potential for exploitation in public-facing or poorly segmented environments.
From a technical perspective, the root cause aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as command injection. The application fails to adequately sanitize user-supplied input before passing it to system-level commands. When a malicious actor crafts a specially formatted request targeting the uploadlangs function, they can inject shell metacharacters that break out of the intended context and execute arbitrary code with the privileges of the web server process or the underlying router firmware. This type of flaw is frequently observed in embedded devices where input validation may be insufficient due to resource constraints or development oversights, allowing attackers to gain full control over the device's operating system.
The operational impact of this vulnerability is severe and comprehensive. Successful exploitation grants an attacker complete administrative access to the DrayTek Vigor2960 router. This level of compromise enables a range of malicious activities including network traffic interception, modification of routing tables to facilitate man-in-the-middle attacks, deployment of malware on connected devices, and use of the compromised device as part of a botnet for distributed denial-of-service attacks. The attacker can also exfiltrate sensitive configuration data such as VPN credentials, ISP login details, and firewall rules. Given that routers often serve as the primary gateway between an internal network and the internet, this vulnerability effectively compromises the entire local area network connected to it.
Industry frameworks categorize this type of attack under ATT&CK technique T1059 Command and Scripting Interpreter, specifically leveraging OS-level command execution via web application vulnerabilities. The lack of input validation represents a fundamental security design flaw that violates principles of secure coding practices outlined in standards such as OWASP Top 10, particularly regarding Injection flaws. Organizations relying on this hardware must recognize that the absence of authentication for certain administrative functions exacerbates the risk profile, making it easier for automated scanning tools and opportunistic attackers to discover and exploit these entry points without needing valid credentials first.
Mitigation strategies primarily involve upgrading the firmware to version 1.5.1.7 or later, which addresses this specific command injection flaw by implementing proper input sanitization in the uploadlangs function. However, it is crucial to note that the DrayTek Vigor2960 has reached its End of Support (EoS) status with limited vendor support available only for major issues like unauthenticated vulnerabilities. This means that while a patch exists for this specific CVE, future security updates or patches for newly discovered flaws may not be provided by the manufacturer. Consequently, relying solely on firmware upgrades is a temporary solution within an already compromised lifecycle.
For long-term risk reduction, organizations should consider replacing the affected Vigor2960 units with supported hardware models that receive regular security updates and maintain active vendor support. In environments where immediate replacement is not feasible, network segmentation can help mitigate the impact by isolating the router from critical internal assets. Additionally, implementing strict access control lists on the management interface to restrict administrative access only to trusted IP addresses can reduce the attack surface. Monitoring logs for unusual outbound connections or configuration changes may also aid in detecting potential exploitation attempts before significant damage occurs.