CVE-2006-5123 in PHProjekt
Summary
by MITRE
Multiple PHP remote file inclusion vulnerabilities in Albrecht Guenther PHProjekt 5.1.x before 5.1.2 allow remote attackers to execute arbitrary PHP code via a URL in the (1) lib_path or (2) lang_path parameter in unspecified files, related to code changes intended to fix inclusion, a different vulnerability than CVE-2002-0451, CVE-2006-4204, and CVE-2006-4609.
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Analysis
by VulDB Data Team • 04/23/2026
The vulnerability identified as CVE-2006-5123 represents a critical remote file inclusion flaw affecting Albrecht Guenther PHProjekt version 5.1.x prior to 5.1.2. This security weakness stems from improper input validation mechanisms within the application's code handling of file path parameters, specifically targeting lib_path and lang_path variables. The vulnerability emerged from code changes intended to address previous inclusion issues, creating a paradoxical situation where the attempted security fix introduced new attack vectors. This flaw enables malicious actors to inject arbitrary PHP code execution by manipulating URL parameters passed to the application's core files, making it particularly dangerous for web applications that rely on dynamic path resolution.
The technical implementation of this vulnerability resides in the application's failure to properly sanitize user-supplied input before using it in file inclusion operations. When the PHProjekt application processes requests containing lib_path or lang_path parameters, it directly incorporates these values into file path constructions without adequate validation or filtering. This allows attackers to specify external URLs that get included and executed as PHP code, effectively bypassing the application's intended security boundaries. The vulnerability operates at the intersection of several cybersecurity principles including input validation, secure coding practices, and the principle of least privilege, as it permits remote code execution through parameter manipulation. This type of vulnerability maps directly to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and specifically relates to the improper handling of dynamic code execution paths.
From an operational impact perspective, this vulnerability presents a severe threat to organizations utilizing PHProjekt 5.1.x versions before 5.1.2, as it allows complete remote code execution capabilities. Attackers can leverage this vulnerability to upload malicious files, establish backdoors, escalate privileges, or compromise entire server infrastructures. The vulnerability's remote nature means that exploitation does not require local system access, making it particularly attractive to threat actors. The attack surface expands significantly since the vulnerability affects multiple unspecified files within the application's codebase, potentially providing multiple entry points for compromise. Security professionals should note that this vulnerability's impact extends beyond simple code execution to include potential data breaches, system reconnaissance, and lateral movement within compromised networks.
Mitigation strategies for CVE-2006-5123 should focus on immediate patch deployment to PHProjekt version 5.1.2 or later, which contains the necessary fixes for the remote file inclusion vulnerability. Organizations should implement proper input validation and sanitization measures to prevent user-supplied parameters from being used in file inclusion operations. The principle of least privilege should be enforced by restricting file inclusion paths to only trusted local directories. Network-level protections including web application firewalls and intrusion detection systems can help detect and block exploitation attempts. Additionally, security configurations should disable remote file inclusion features entirely when possible, and all file paths should be validated against a strict whitelist of acceptable values. According to ATT&CK framework category T1190, this vulnerability aligns with "Exploit Public-Facing Application" techniques, while the exploitation methods correspond to T1059.007 for "Command and Scripting Interpreter: PowerShell" and T1059.001 for "Command and Scripting Interpreter: PowerShell" in contexts where PHP execution is involved. Organizations should also consider implementing security monitoring and logging for file inclusion operations to detect anomalous behavior patterns that may indicate exploitation attempts.