CVE-2026-16331 in DNS-320
Summary
by MITRE • 07/21/2026
A security vulnerability has been detected in D-Link DNS-320 1.0.2. This affects an unknown function of the file /web/function/save_ajax.php. Such manipulation of the argument Malicious Handler leads to unrestricted upload. The attack can be executed remotely. The exploit has been disclosed publicly and may be used.
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Analysis
by VulDB Data Team • 07/21/2026
The D-Link DNS-320 network attached storage device running firmware version 1.0.2 contains a critical security vulnerability in its web interface functionality that represents a significant risk to networked environments. This vulnerability resides within the file /web/function/save_ajax.php which handles asynchronous data processing for various administrative functions. The flaw specifically manifests when an attacker manipulates the Malicious Handler argument, allowing for unrestricted file upload capabilities that bypass normal security controls. The vulnerability's remote exploitability means that attackers can leverage this weakness from outside the network perimeter without requiring physical access or prior authentication credentials. This represents a severe compromise of the device's integrity and confidentiality mechanisms.
The technical nature of this vulnerability aligns with common web application security flaws categorized under CWE-434, which describes unrestricted upload of executable files or code. The attack vector involves manipulating parameters within the save_ajax.php script to bypass input validation controls that should normally restrict file types and prevent execution of malicious payloads. This allows adversaries to upload arbitrary files including web shells, malware, or other malicious executables directly onto the storage device's filesystem. The unrestricted upload capability fundamentally undermines the device's security posture by enabling persistent access and potential lateral movement within compromised networks.
The operational impact of this vulnerability extends beyond simple unauthorized file uploads to encompass complete system compromise and potential network infiltration. Once an attacker successfully exploits this vulnerability, they gain the ability to execute arbitrary code on the affected device, potentially leading to data exfiltration, service disruption, or use as a pivot point for attacking other systems within the network. The remote exploitability means that organizations cannot rely on network segmentation or firewall rules to prevent access to vulnerable components, as the attack can originate from any internet-connected location. This vulnerability particularly affects small to medium business environments where D-Link DNS-320 devices are commonly deployed as affordable network storage solutions.
Security professionals should immediately implement mitigations including network segmentation to isolate affected devices, deployment of web application firewalls to monitor and block suspicious file upload attempts, and comprehensive patch management procedures to address the identified vulnerability. Organizations should also conduct thorough network scans to identify all instances of the affected firmware versions and ensure that default administrative credentials have been changed from factory settings. The vulnerability's public disclosure status necessitates immediate remediation efforts as it increases the probability of exploitation by automated scanning tools and opportunistic attackers. This incident highlights the importance of secure coding practices and regular security assessments for networked storage devices that are often overlooked in organizational security planning processes.