CVE-2026-71926 in VigorSwitch
Summary
by MITRE • 08/24/2026
Multiple DrayTek VigorSwitch models contain a command injection vulnerability in the setDevice function. The vulnerability is caused by insufficient sanitization of the username, password, and location fields before command execution. A remote attacker can trigger this vulnerability via crafted input to execute arbitrary commands with root privileges. Exploitation requires valid administrative credentials for the device's web management interface.
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Analysis
by VulDB Data Team • 08/24/2026
The DrayTek VigorSwitch series contains a critical security flaw within its embedded web management interface, specifically affecting the setDevice function responsible for configuring network parameters. This vulnerability stems from insufficient input validation and sanitization mechanisms applied to user-supplied data fields, namely username, password, and location attributes. When these inputs are processed by the underlying system commands without proper escaping or filtering of special characters, they allow an attacker to inject arbitrary shell commands into the execution context. The root cause lies in the application's failure to strictly enforce input constraints, treating potentially malicious payloads as legitimate configuration data rather than rejecting them based on predefined safe character sets or structural validation rules.
From a technical perspective, this flaw represents a classic command injection vulnerability where user-controlled input is directly concatenated with system commands without adequate separation. The lack of sanitization means that characters such as semicolons, pipes, and backticks can be used to break out of the intended parameter scope and execute subsequent shell operations. Because the affected function operates within an administrative context, the injected commands are executed with elevated privileges, typically root level access on the device's operating system. This allows for complete compromise of the network switch's integrity, enabling attackers to modify firmware, exfiltrate sensitive configuration data, or pivot into other segments of the internal network infrastructure protected by the switch.
The operational impact of this vulnerability is severe due to its potential for remote code execution with high privilege levels. Although exploitation requires valid administrative credentials for the web management interface, which may seem like a mitigating factor, it does not eliminate risk in environments where credential theft via phishing, brute force attacks, or weak password policies is prevalent. Once an attacker gains access through compromised credentials, they can leverage this command injection to gain full control over the device. This capability facilitates lateral movement within the network, allowing attackers to intercept traffic, perform man-in-the-middle attacks, or deploy persistent backdoors that are difficult to detect using standard security monitoring tools.
To mitigate this risk, organizations must immediately apply vendor-provided firmware updates that address the input validation deficiencies in the setDevice function. Until patches are available, it is crucial to restrict access to the web management interface through strict network segmentation and firewall rules, ensuring only authorized IP addresses can reach the administrative ports. Additionally, enforcing strong password policies and multi-factor authentication for administrative accounts significantly reduces the likelihood of credential compromise that precedes exploitation. Regular vulnerability scanning and continuous monitoring of device logs for anomalous configuration changes are also recommended to detect potential attempts at exploiting this flaw before full system takeover occurs. This issue aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command, highlighting the necessity of rigorous input sanitization practices in embedded web applications.