CVE-2009-4726 in Quickdev4php
Summary
by MITRE
Directory traversal vulnerability in download.php in Quickdev 4 PHP allows remote attackers to read arbitrary files via a .. (dot dot) in the file parameter.
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Analysis
by VulDB Data Team • 05/02/2026
The vulnerability identified as CVE-2009-4726 represents a critical directory traversal flaw within the Quickdev 4 PHP framework's download.php script. This security weakness stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied file parameters before processing file system requests. The vulnerability specifically manifests when the application accepts a file parameter containing directory traversal sequences such as .. which allows attackers to navigate outside the intended directory boundaries and access files that should remain restricted. The flaw resides in the application's file handling logic where user input directly influences file system operations without proper sanitization or validation checks. This creates an exploitable condition where remote attackers can manipulate the file parameter to traverse directories and potentially access sensitive system files, configuration data, or other restricted resources within the application's file system hierarchy. The vulnerability impacts the confidentiality and integrity of the affected system as it enables unauthorized file access that could lead to data breaches or further exploitation opportunities. This type of vulnerability is classified under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The attack vector is particularly concerning as it allows remote exploitation without requiring authentication or prior access to the system, making it a significant threat to web application security. The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can potentially expose sensitive information such as database credentials, application source code, or system configuration files that could be leveraged for additional attacks. The vulnerability's presence in a download script is particularly dangerous as it directly interacts with the file system and can be exploited through simple web requests that manipulate the file parameter to access unintended resources. This weakness demonstrates poor input validation practices and highlights the importance of implementing proper access controls and file system boundary checks in web applications. The vulnerability aligns with ATT&CK technique T1083 which describes discovering file and directory permissions on compromised systems, as successful exploitation would provide attackers with information about the system's file structure and access patterns. The security implications are compounded by the fact that such vulnerabilities often remain undetected for extended periods, providing attackers with persistent access to sensitive resources. Organizations using Quickdev 4 PHP should immediately implement input validation measures to sanitize all user-supplied file parameters and ensure that file system operations are properly constrained to intended directories. The recommended mitigations include implementing whitelist-based validation for file parameters, using absolute path resolution to prevent directory traversal attempts, and restricting file access to specific directories through proper configuration. Additionally, developers should adopt secure coding practices that enforce proper input validation and implement proper error handling to prevent information disclosure that could aid attackers in exploiting similar vulnerabilities. The vulnerability underscores the critical need for regular security assessments and code reviews to identify and remediate such path traversal vulnerabilities before they can be exploited by malicious actors.