CVE-2022-40720 in DIR-2150
Summary
by MITRE • 01/26/2023
This vulnerability allows network-adjacent attackers to execute arbitrary commands on affected installations of D-Link DIR-2150 4.0.1 routers. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the Dreambox plugin for the xupnpd service, which listens on TCP port 4044 by default. The issue results from the lack of proper validation of a user-supplied string before using it to execute a system call. An attacker can leverage this vulnerability to execute code in the context of the router. Was ZDI-CAN-15935.
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Analysis
by VulDB Data Team • 09/06/2026
The D-Link DIR-2150 version 4.0.1 firmware contains a critical remote code execution vulnerability within its UPnP implementation, specifically affecting the Dreambox plugin associated with the xupnpd service. This service typically listens on TCP port 4044 and is designed to handle Universal Plug and Play requests from devices on the local network segment. The core technical flaw stems from an improper validation of user-supplied input strings before they are passed directly into system calls for execution. Because this component processes incoming UPnP messages without sanitizing or validating the data, it creates a classic command injection vector that allows attackers to inject arbitrary shell commands into the router's operating environment.
From a security architecture perspective, this vulnerability is particularly severe because it does not require any form of authentication prior to exploitation. Network-adjacent attackers, meaning anyone with connectivity to the same local area network as the compromised device, can initiate the attack sequence immediately upon connection. The lack of access controls means that malicious actors do not need valid credentials or prior compromise of user accounts to trigger the flaw. This characteristic significantly lowers the barrier for entry, enabling opportunistic attacks by individuals who may have physical proximity to the target network or control over a compromised device on the same subnet.
The operational impact of this vulnerability is profound, as successful exploitation grants an attacker full command execution capabilities within the context of the router's operating system. Depending on how the xupnpd service is configured and what privileges it holds during runtime, this often equates to root-level access or equivalent administrative privileges. With such elevated control, an adversary can modify network configurations, install persistent backdoors, redirect traffic for man-in-the-middle attacks, or use the router as a pivot point to launch further attacks against other devices on the internal network. The compromise of internet-facing infrastructure like routers also poses significant risks to data privacy and integrity across the entire connected ecosystem.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-78, which describes Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. In terms of offensive security tactics, this exploitation method corresponds to MITRE ATT&CK technique T1059, specifically sub-techniques involving command and script interpreters such as Unix Shell or Windows Command Shell. The attack vector is classified under Network Adjacent access with no required privileges, highlighting the ease with which local network threats can escalate into full system compromise when input validation mechanisms are absent in embedded services.
Mitigation strategies for this vulnerability primarily involve applying vendor-provided firmware updates that address the input sanitization logic within the Dreambox plugin and xupnpd service. If immediate patching is not feasible, administrators should consider disabling UPnP functionality entirely if it is not strictly required for network operations, thereby removing the attack surface associated with port 4044. Additionally, implementing strict firewall rules to restrict access to management interfaces and embedded services from untrusted networks can provide a layer of defense-in-depth. Regular monitoring of router logs for unusual outbound connections or unexpected process executions may also aid in early detection of exploitation attempts while longer-term remediation plans are executed.