CVE-2024-46986: 
Ruby vulnerability analysis and mitigation

Camaleon CMS, a dynamic content management system based on Ruby on Rails, contains a critical arbitrary file write vulnerability (CVE-2024-46986) discovered in versions prior to 2.8.2. The vulnerability allows authenticated users to write arbitrary files to any location on the web server where Camaleon CMS is running, with the scope limited only by the underlying filesystem permissions. This security flaw was disclosed on September 18, 2024, and received a CVSS v3.1 score of 9.9 (Critical) (GitHub Advisory).

The vulnerability exists in the upload method of the MediaController, where the fileupload and folder parameters are passed to the uploadfile method without proper path validation. The application fails to properly sanitize or validate the folder parameter, allowing directory traversal through path manipulation. An attacker can use relative path sequences (../) to write files outside the intended directory structure. The vulnerability is particularly concerning as it bypasses format restrictions when the formats parameter is removed, allowing upload of arbitrary file types (GitHub Advisory, CodeQL Guide).

The vulnerability can lead to remote code execution (RCE) if an attacker successfully writes a malicious Ruby file into sensitive locations such as the config/initializers/ subfolder of the Ruby on Rails application. This could result in complete system compromise, allowing attackers to execute arbitrary code, access sensitive information, or modify system files (GitHub Advisory, Security Online).

The vulnerability has been patched in Camaleon CMS version 2.8.2. Users are strongly advised to upgrade to this version immediately. For those unable to upgrade immediately, it is recommended to implement strict input validation for file paths, normalize file paths constructed from user input, and prevent the use of directory traversal sequences such as '../' in file operations (GitHub Advisory, OWASP Guide).