CVE-2006-5833 in GreenBeast CMS
Summary
by MITRE
gbcms_php_files/up_loader.php GreenBeast CMS 1.3 does not require authentication to upload files, which allows remote attackers to cause a denial of service (disk consumption) and execute arbitrary code by uploading arbitrary files, such as executing PHP code via an uploaded PHP file.
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Analysis
by VulDB Data Team • 04/27/2026
The vulnerability identified as CVE-2006-5833 affects GreenBeast CMS version 1.3 and represents a critical security flaw in the file upload functionality of the up_loader.php component. This issue stems from the absence of proper authentication mechanisms within the file upload process, creating an exploitable condition that allows unauthorized remote attackers to gain unrestricted access to the system's file upload capabilities. The flaw exists in the gbcms_php_files directory structure and specifically targets the up_loader.php script that handles file uploads within the content management system.
The technical nature of this vulnerability aligns with CWE-225, which describes improper restriction of operations within a limited context, and CWE-434, which addresses insecure file upload handling. The absence of authentication requirements means that any remote attacker can directly access the upload endpoint without providing valid credentials, bypassing all security controls that should normally be enforced. This authentication bypass creates a path for attackers to upload malicious files to the target system, potentially leading to complete system compromise. The vulnerability specifically allows for arbitrary file execution through PHP code injection, as attackers can upload PHP files that will be executed by the web server.
The operational impact of this vulnerability is severe and multifaceted, encompassing both denial of service and arbitrary code execution capabilities. Attackers can consume disk space rapidly by uploading large files, leading to denial of service conditions that prevent legitimate users from accessing the system or uploading necessary files. More critically, the ability to upload PHP files enables attackers to execute arbitrary code on the target system, potentially allowing them to establish persistent backdoors, escalate privileges, or exfiltrate sensitive data. This vulnerability effectively transforms the CMS into an attack vector that can be exploited to compromise the entire web server infrastructure, making it particularly dangerous for systems hosting sensitive information or serving critical business functions.
The exploitation of this vulnerability follows patterns consistent with ATT&CK technique T1190, which involves exploiting vulnerabilities in remote services to gain initial access. The lack of authentication requirements provides attackers with a direct path to execute malicious payloads, while the PHP execution capability enables them to perform further reconnaissance and lateral movement within the compromised network. Organizations should consider implementing network segmentation and access controls to limit exposure, while also deploying web application firewalls to monitor and block suspicious file upload activities. Regular security assessments and vulnerability scanning should be conducted to identify similar authentication bypass vulnerabilities in other components of the CMS or related applications, as this type of flaw often indicates broader architectural security weaknesses that may affect multiple system components.