CVE-2026-4499 in DIR-820LW
Summary
by MITRE • 03/20/2026
A vulnerability was determined in D-Link DIR-820LW 2.03. Affected is the function ssdpcgi_main of the component SSDP. Executing a manipulation can lead to os command injection. The attack may be launched remotely. The exploit has been publicly disclosed and may be utilized.
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Analysis
by VulDB Data Team • 03/27/2026
The vulnerability identified as CVE-2026-4499 affects the D-Link DIR-820LW 2.03 wireless router model, specifically within the Simple Service Discovery Protocol (SSDP) component. This issue resides in the ssdpcgi_main function which handles network service discovery operations. The affected device operates under the assumption that incoming requests from the network are trustworthy, creating an environment where malicious actors can manipulate input parameters without proper validation. The vulnerability stems from insufficient sanitization of user-supplied data that flows into operating system command execution contexts, representing a classic command injection flaw that allows arbitrary code execution on the affected device.
This vulnerability presents a significant security risk as it enables remote code execution through the SSDP protocol which is designed to facilitate network discovery services. The attack vector requires no authentication and can be exploited from external network positions, making it particularly dangerous for devices deployed in residential or small office environments. The command injection occurs when malformed input data is processed by the ssdpcgi_main function and subsequently passed to system commands without proper escaping or filtering. This flaw aligns with CWE-77 and CWE-88 categories under the Common Weakness Enumeration framework, specifically addressing improper neutralization of special elements used in OS commands and command injection vulnerabilities.
The operational impact of this vulnerability extends beyond simple unauthorized access as it allows attackers to completely compromise the router's functionality. An attacker could gain full control over the device, potentially redirecting traffic, modifying network settings, or using the compromised router as a pivot point for attacking other devices on the local network. The exploitation process involves sending specially crafted SSDP packets that trigger the vulnerable code path, enabling the execution of arbitrary operating system commands with the privileges of the web server process. This represents a critical security gap that violates fundamental security principles of input validation and privilege separation, as outlined in the MITRE ATT&CK framework under the T1059.001 technique for command and scripting interpreter.
Mitigation strategies for this vulnerability should include immediate firmware updates from D-Link to address the command injection flaw in the SSDP component. Network administrators should also implement network segmentation to limit the exposure of such devices to external networks and consider disabling unnecessary services like SSDP when not required for network operations. Additional protective measures include deploying network intrusion detection systems that can identify suspicious SSDP traffic patterns and implementing proper access controls that restrict network access to only authorized users. The vulnerability demonstrates the importance of secure coding practices and input validation, particularly in network services that handle external communications, emphasizing the need for defense-in-depth strategies that protect against both known and unknown threats in network infrastructure devices.