CVE-2006-5148 in Forum82
Summary
by MITRE
Multiple PHP remote file inclusion vulnerabilities in Forum82 2.5.2b and earlier allow remote attackers to execute arbitrary PHP code via a URL in the repertorylevel parameter including scripts in /forum/ including (1) search.php, (2) message.php, (3) member.php, (4) mail.php, (5) lostpassword.php, (6) gesfil.php, (7) forum82lib.php3, and other unspecified scripts.
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Analysis
by VulDB Data Team • 04/23/2026
The vulnerability identified as CVE-2006-5148 represents a critical remote file inclusion flaw affecting Forum82 version 2.5.2b and earlier installations. This vulnerability resides in the application's handling of user-supplied input within the repertorylevel parameter, which is processed across multiple script files including search.php, message.php, member.php, mail.php, lostpassword.php, gesfil.php, and forum82lib.php3 among others. The flaw stems from improper input validation and sanitization mechanisms that fail to adequately filter or escape user-provided URLs before incorporating them into the application's execution flow.
This vulnerability classifies under CWE-88, which describes improper neutralization of special elements used in an OS command, and more specifically aligns with CWE-94, which addresses the execution of arbitrary code due to insufficient input validation. The vulnerability enables attackers to inject malicious URLs that are then executed by the PHP interpreter, effectively allowing remote code execution on the affected server. The impact is particularly severe as it affects multiple entry points within the application's core functionality, providing attackers with multiple potential attack vectors to exploit the same underlying flaw.
The operational impact of this vulnerability extends far beyond simple data theft or service disruption. Attackers can leverage this flaw to execute arbitrary PHP code on the target server, potentially gaining full administrative control over the affected system. This capability allows for persistent backdoor installation, data exfiltration, server compromise, and further lateral movement within the network. The vulnerability's presence in core forum scripts means that legitimate users' interactions with the application can be exploited to deliver malicious payloads, making detection and mitigation particularly challenging.
From a threat modeling perspective, this vulnerability maps directly to ATT&CK technique T1190, which describes the exploitation of remote services through the use of malicious code injection. The attack surface is amplified by the fact that multiple scripts are vulnerable, increasing the probability of successful exploitation. Security professionals should note that this vulnerability represents a classic example of a dangerous input handling flaw that was prevalent in web applications of that era, highlighting the importance of implementing proper input validation and output encoding mechanisms. The vulnerability demonstrates the critical need for secure coding practices, specifically the principle of least privilege and the importance of validating all user inputs before processing them within the application context.
Mitigation strategies should include immediate patching of the affected Forum82 versions to the latest available security updates. Organizations should implement proper input validation mechanisms that reject or sanitize any URLs containing suspicious characters or patterns. Network segmentation and firewall rules can help limit access to vulnerable scripts, while web application firewalls should be configured to detect and block malicious URL patterns. Additionally, the principle of least privilege should be enforced by ensuring that web applications run with minimal necessary permissions, and regular security audits should be conducted to identify similar vulnerabilities in other applications. The vulnerability also underscores the importance of keeping all third-party components updated and maintaining comprehensive security monitoring to detect exploitation attempts.