CVE-2007-6650 in R2 CMS
Summary
by MITRE
Unrestricted file upload vulnerability in fisheye/upload.php in Bitweaver R2 CMS allows remote attackers to upload arbitrary files by using the image/gif content type, and possibly other image and PDF content types, as demonstrated by uploading a .htaccess file.
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Analysis
by VulDB Data Team • 06/22/2025
The vulnerability described in CVE-2007-6650 represents a critical unrestricted file upload flaw within the Bitweaver R2 Content Management System, specifically affecting the fisheye/upload.php component. This vulnerability exposes the system to remote code execution risks through improper input validation and content type handling mechanisms. The flaw allows attackers to bypass security restrictions by leveraging legitimate image content types such as image/gif and potentially other image formats along with PDF content types to upload malicious files. The attack vector demonstrates a sophisticated understanding of how web applications process file uploads and content type validation, exploiting the trust placed in specific MIME types to execute arbitrary code on the target server.
The technical implementation of this vulnerability stems from inadequate validation of file content and MIME type checking within the upload.php script. When attackers submit files with image/gif content type, the system accepts these uploads without proper verification of the actual file content, allowing malicious payloads to be stored on the server. The demonstration of uploading .htaccess files indicates that attackers can manipulate server configurations and potentially execute code through the uploaded files. This vulnerability directly relates to CWE-434 which categorizes insecure file upload handling, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications to gain initial access.
The operational impact of this vulnerability extends beyond simple file upload capabilities, as it enables full system compromise through remote code execution. Attackers can upload web shells, backdoors, or other malicious scripts that persist on the server and provide ongoing access to the compromised system. The ability to upload .htaccess files specifically allows for manipulation of server configuration directives, potentially enabling directory traversal attacks, custom error pages, or even rewriting URLs to redirect traffic. This vulnerability effectively eliminates the server's ability to protect against malicious uploads through content type validation mechanisms.
Mitigation strategies for this vulnerability require immediate implementation of multiple defense layers including strict file content validation, proper MIME type verification, and comprehensive file extension filtering. Organizations should implement whitelisting of allowed file types and enforce server-side validation of actual file content rather than relying solely on client-provided MIME types. The solution involves configuring the web application to perform thorough file analysis and reject any uploads that do not match expected content patterns. Additionally, restricting upload directories permissions, implementing proper access controls, and ensuring that uploaded files are not directly executable from web-accessible directories are essential measures. Security hardening should include regular vulnerability assessments and patch management procedures to prevent similar issues in future deployments.