CVE-2025-69906 in Monstra
Summary
by MITRE • 02/05/2026
Monstra CMS v3.0.4 contains an arbitrary file upload vulnerability in the Files Manager plugin. The application relies on blacklist-based file extension validation and stores uploaded files directly in a web-accessible directory. Under typical server configurations, this can allow an attacker to upload files that are interpreted as executable code, resulting in remote code execution.
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Analysis
by VulDB Data Team • 02/12/2026
The vulnerability identified as CVE-2025-69906 affects Monstra CMS version 3.0.4 and stems from a critical flaw in the Files Manager plugin that enables arbitrary file upload capabilities. This issue represents a fundamental security weakness in the content management system's file handling mechanisms, where the application fails to implement robust validation controls for uploaded content. The vulnerability manifests due to the application's reliance on blacklist-based file extension validation rather than whitelist-based approaches, which is a known security anti-pattern that significantly increases the attack surface and risk exposure.
The technical implementation of this vulnerability occurs within the Files Manager plugin where uploaded files are processed without adequate sanitization or verification of their content type and file extension. The application stores these files directly in web-accessible directories, creating a direct pathway for attackers to execute malicious code through file uploads. This configuration allows an attacker to bypass the security controls by uploading files with extensions that are not properly blacklisted or by exploiting server misconfigurations that permit execution of certain file types. The combination of weak validation logic and insecure file storage creates a dangerous environment where attackers can upload malicious files that are subsequently interpreted and executed by the web server.
The operational impact of this vulnerability is severe and can result in complete system compromise, as remote code execution enables attackers to gain unauthorized access to the underlying server infrastructure. Attackers can upload web shells, malicious scripts, or other exploit payloads that can be executed with the privileges of the web server process. This vulnerability can lead to data breaches, system infiltration, and potential lateral movement within network environments where the CMS is deployed. The attack vector is particularly concerning because it requires minimal privileges to exploit and can be automated, making it attractive to both automated scanning tools and targeted attackers seeking to compromise web applications. The vulnerability also affects the integrity and confidentiality of all data managed through the CMS, as attackers can access, modify, or exfiltrate sensitive information stored within the system.
Mitigation strategies for this vulnerability should focus on implementing proper file validation controls and secure file handling practices. Organizations should immediately implement whitelist-based file extension validation rather than relying on blacklist approaches, ensuring that only explicitly allowed file types are accepted for upload. The Files Manager plugin should be updated to the latest version that addresses this vulnerability, and if an update is not immediately available, administrators should consider implementing additional security layers such as web application firewalls or file integrity monitoring systems. Server configurations should be reviewed to ensure that uploaded files are stored outside of web-accessible directories or that proper access controls are implemented to prevent execution of uploaded content. This vulnerability aligns with CWE-434 which specifically addresses insecure file upload vulnerabilities, and the attack pattern corresponds to techniques described in the ATT&CK framework under T1190 for exploitation of remote services and T1059 for command and scripting interpreter usage. Regular security assessments and input validation testing should be conducted to prevent similar issues in other components of the CMS and to maintain overall system security posture.