CVE-2026-94104 in NivoCart
Summary
by MITRE • 09/20/2026
NivoCart through 2.4.0 contains an arbitrary file upload vulnerability in the File Manager multi() endpoint that fails to validate file extensions for new filenames or when chunks parameter is 2 or higher. Attackers with view-only back-office access can upload PHP files to the web-accessible image/data/ directory and execute them for remote code execution.
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Analysis
by VulDB Data Team • 09/20/2026
The vulnerability identified in NivoCart versions up to 2.4.0 represents a critical security flaw within its File Manager component, specifically targeting the multi() endpoint responsible for handling file uploads. This weakness stems from an insufficient validation mechanism that fails to rigorously check file extensions when new filenames are provided or when the upload process involves chunked transfers with a parameter value of two or higher. In typical web application architectures, file upload functionality is often one of the most sensitive areas due to its direct interaction with the server's filesystem and potential for code execution if mishandled. The specific failure here lies in the logic that processes these uploads, where the system does not adequately sanitize or verify the type of content being uploaded under certain conditions, allowing malicious actors to bypass standard security controls designed to prevent executable script injection.
From a technical perspective, this flaw is classified as an Arbitrary File Upload vulnerability, which aligns with CWE-434 in the Common Weakness Enumeration standards. The core issue involves the application's inability to distinguish between benign files and potentially dangerous scripts due to flawed extension checking logic. When an attacker interacts with the multi() endpoint using specific parameters that trigger chunked processing or custom filename handling, the server accepts PHP file extensions without proper verification against a whitelist of allowed types. This oversight permits the storage of executable code directly onto the web server's document root, specifically within the image/data/ directory which is typically configured to be publicly accessible via HTTP requests.
The operational impact of this vulnerability is severe, as it facilitates Remote Code Execution (RCE) for attackers who possess even minimal privileges such as view-only access in the back-office administration panel. This low barrier to entry significantly expands the attack surface, allowing individuals with limited legitimate access to escalate their privileges effectively by uploading and executing malicious PHP scripts. Once a PHP file is successfully uploaded to the web-accessible directory, an attacker can invoke it through a standard HTTP request, thereby gaining full control over the underlying server environment. This capability enables data exfiltration, modification of application logic, installation of backdoors, or use of the compromised system as a pivot point for further network intrusions, fundamentally breaking the confidentiality and integrity guarantees expected from the platform.
In terms of threat modeling, this vulnerability maps to several techniques within the MITRE ATT&CK framework. The initial access phase is covered by T1505.003, which refers to Web Shell: Server Side Script, as the uploaded PHP file acts as a web shell allowing persistent remote control. Additionally, the exploitation of insufficient input validation relates to T1190, Exploit Public-Facing Application, particularly when combined with the low privilege requirement that allows unauthorized users to initiate the attack vector. The ability to execute arbitrary code on the server also aligns with T1059, Command and Scripting Interpreter, specifically through the use of PHP scripts to run system commands or manipulate application state remotely.
Mitigation strategies must focus on immediate remediation of the file upload logic within the NivoCart File Manager component. Developers should implement strict allow-list validation for all uploaded files, ensuring that only predefined safe extensions such as jpg, png, and gif are accepted, regardless of how the filename is constructed or whether chunked uploads are utilized. It is crucial to enforce this validation both on the client side for user experience and, more importantly, on the server side where security controls reside. Furthermore, configuring the web server to disable script execution in directories designated solely for static assets like images can provide a robust defense-in-depth layer. Even if an attacker manages to upload a malicious file, disabling PHP execution in that specific directory will prevent the code from running, thereby neutralizing the remote code execution risk until a permanent patch is applied by the vendor.