CVE-2006-5566 in Shop-Script
Summary
by MITRE
CRLF injection vulnerability in premium/index.php in Shop-Script allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via CRLF sequences in the (1) links_exchange, (2) news, (3) search_with_change_category_ability, (4) logging, (5) feedback, (6) show_price, (7) register, (8) answer, (9) productID, and (10) inside parameters.
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Analysis
by VulDB Data Team • 04/25/2026
The CVE-2006-5566 vulnerability represents a critical CRLF injection flaw in the Shop-Script e-commerce platform's premium/index.php component. This vulnerability stems from inadequate input validation and sanitization of user-supplied parameters, specifically affecting ten distinct parameter names including links_exchange, news, search_with_change_category_ability, logging, feedback, show_price, register, answer, productID, and inside. The flaw allows remote attackers to inject malicious carriage return line feed sequences that can manipulate HTTP headers and execute HTTP response splitting attacks. The vulnerability operates at the application layer and directly impacts the integrity of HTTP responses generated by the web server.
The technical exploitation of this vulnerability occurs when user input containing CRLF sequences is processed without proper sanitization before being included in HTTP response headers or body content. Attackers can leverage this weakness to inject arbitrary HTTP headers, manipulate response content, and potentially redirect users to malicious websites through HTTP response splitting techniques. The vulnerability is particularly dangerous because it affects multiple parameter types within the same vulnerable script, expanding the attack surface and providing multiple entry points for exploitation. This flaw falls under CWE-113, which specifically addresses improper neutralization of CRLF sequences in HTTP headers, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications.
The operational impact of this vulnerability extends beyond simple header injection, as it can enable sophisticated attack vectors including session hijacking, cross-site scripting attacks, and cache poisoning. An attacker who successfully exploits this vulnerability could manipulate the web server's response headers to inject malicious content, redirect users to phishing sites, or even bypass security mechanisms such as content security policies. The vulnerability particularly affects online businesses using Shop-Script, potentially compromising customer data, session information, and the overall integrity of the e-commerce platform. Organizations with vulnerable systems could face significant reputational damage, financial loss, and regulatory compliance issues. The exploitation of this vulnerability requires minimal technical skill and can be automated, making it particularly dangerous in environments where proper input validation is not implemented.
Mitigation strategies for CVE-2006-5566 require immediate implementation of proper input validation and sanitization measures across all user-supplied parameters. Organizations should implement strict filtering of CRLF sequences in all HTTP headers and response content, employ proper parameter validation techniques, and ensure that all user inputs are properly escaped before being processed by the application. The solution involves implementing input sanitization at multiple levels including application code, web server configuration, and database input handling. Security measures should include regular security audits, input validation frameworks, and comprehensive testing procedures to identify similar vulnerabilities in other components of the web application. Additionally, implementing proper HTTP header management and response handling practices can significantly reduce the risk of exploitation. Organizations should also consider deploying web application firewalls and monitoring systems to detect and prevent exploitation attempts. The vulnerability demonstrates the critical importance of implementing defense-in-depth strategies and proper security coding practices to prevent similar issues in future development cycles.