CVE-2026-71905 in VigorAP
Summary
by MITRE • 08/24/2026
Multiple DrayTek VigorAP models contain a command injection vulnerability in the ExportSettings function. The vulnerability is caused by insufficient filtering of the backupkey, backuptype, and realtime 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 VigorAP series of wireless access points contains a critical security flaw within its ExportSettings function, which is designed to allow administrators to back up configuration data. This vulnerability stems from insufficient input validation and sanitization mechanisms applied to specific parameters passed during the export process. Specifically, the fields labeled backupkey, backuptype, and realtime are not adequately filtered before being incorporated into system commands executed by the underlying operating system. When a user requests an export of device settings, these values are directly concatenated or interpolated into shell commands without proper escaping or restriction to expected character sets. This architectural oversight creates a classic command injection vector that allows for arbitrary code execution on the target appliance.
From a technical perspective, this flaw represents a failure in input validation and sanitization practices commonly associated with CWE-78 Improper Neutralization of Special Elements used in an OS Command. The vulnerability is particularly severe because it grants attackers the ability to execute commands with root privileges, which are equivalent to full administrative control over the device's operating system. By crafting malicious payloads within the backupkey or backuptype fields, a remote actor can inject shell metacharacters such as semicolons, pipes, or ampersands. These characters allow the attacker to terminate the intended command and append arbitrary instructions that are then executed by the privileged process handling the export operation. This effectively bypasses any sandboxing or restricted user contexts that might otherwise limit the impact of a compromised web interface.
The operational impact of this vulnerability is profound, as it compromises the entire integrity and availability of the network infrastructure managed by the affected VigorAP devices. An attacker who successfully exploits this flaw can install persistent backdoors, exfiltrate sensitive configuration data including Wi-Fi passwords and firewall rules, or pivot to other systems on the internal network using the compromised device as a foothold. Furthermore, because the vulnerability resides in a function accessible via the web management interface, it directly impacts the confidentiality and integrity of administrative controls. The ability to execute commands with root privileges means that an attacker can modify system binaries, disable logging mechanisms, or establish reverse shells that provide persistent remote access even after reboots if persistence mechanisms are implemented.
Exploitation of this vulnerability requires valid administrative credentials for the device's web management interface. This constraint places the risk primarily in scenarios where credential theft occurs through phishing, brute force attacks against weak passwords, or exposure of session tokens via other vulnerabilities such as cross-site scripting or insecure direct object references. While it is not a fully unauthenticated remote code execution flaw, the low barrier to entry for obtaining administrative access makes this vulnerability highly exploitable in environments with poor password hygiene or where default credentials remain unchanged. The requirement for authentication does not mitigate the severity of the resulting privilege escalation; rather, it defines the initial attack vector as an authenticated insider threat or a compromised admin account.
To mitigate this risk, organizations must immediately apply vendor-provided firmware updates that address the input validation flaws in the ExportSettings function. Until patches are available, administrators should restrict access to the web management interface using strict firewall rules, allowing connections only from trusted IP addresses and disabling remote administration if not strictly necessary. Implementing multi-factor authentication for administrative accounts can also reduce the likelihood of credential compromise leading to exploitation. Additionally, network segmentation strategies should be employed to limit lateral movement in case a device is compromised. Regular audits of configuration exports and monitoring for unusual outbound traffic patterns can aid in early detection of potential exploitation attempts. Adhering to these controls aligns with ATT&CK techniques related to Command and Scripting Interpreter abuse and Initial Access via valid accounts, helping defenders anticipate and block such attack paths effectively.