CVE-2006-5321 in PHPList
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in phplist before 2.10.3 allow remote attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 04/24/2026
The vulnerability identified as CVE-2006-5321 represents a critical security flaw in the phplist email marketing platform version 2.10.2 and earlier. This vulnerability manifests as multiple cross-site scripting vulnerabilities that create opportunities for remote attackers to execute malicious web scripts or HTML code within the context of affected systems. The issue stems from insufficient input validation and output sanitization mechanisms within the application's codebase, particularly in areas handling user-supplied data that flows into web page responses. These vulnerabilities fall under the CWE-79 category of Cross-Site Scripting, which is a pervasive weakness affecting web applications globally. The vulnerability affects the core functionality of phplist by allowing unauthorized code execution in the browser contexts of legitimate users who interact with compromised application interfaces.
The technical implementation of this vulnerability occurs through unspecified vectors that likely involve form inputs, URL parameters, or data fields within the phplist application's user interface. Attackers can exploit these vectors by crafting malicious payloads that contain script tags or other HTML elements designed to execute in the victim's browser environment. The lack of proper sanitization means that user-controllable data enters the application's response without adequate filtering or encoding, creating a pathway for malicious code injection. This flaw particularly impacts the application's ability to maintain secure communication channels between users and the server, as it allows attackers to manipulate the presentation layer of the application. The vulnerability's impact extends beyond simple script execution to potentially enable session hijacking, credential theft, or redirection to malicious sites, depending on the context in which the injected code executes.
The operational impact of CVE-2006-5321 is significant for organizations utilizing phplist for email marketing campaigns, as it compromises the integrity and security of their communication systems. When exploited, these vulnerabilities can lead to unauthorized access to user sessions, data exfiltration, and potential compromise of the entire email distribution infrastructure. The remote nature of the attack means that threat actors can exploit these flaws from anywhere on the internet without requiring physical access to the target system. Organizations may experience reputational damage when users discover that their email communications have been compromised, and the vulnerability could facilitate phishing attacks or other social engineering campaigns that leverage the trusted phplist interface. The attack surface is particularly concerning given that phplist is commonly used for sending newsletters and marketing communications, making it a prime target for attackers seeking to exploit user trust in legitimate email sources.
Mitigation strategies for CVE-2006-5321 should prioritize immediate patching of affected phplist installations to version 2.10.3 or later, which contains the necessary security fixes. Organizations should implement comprehensive input validation and output encoding mechanisms to prevent malicious data from being executed as code within the application's response context. The implementation of Content Security Policy headers can provide additional protection against script execution, while regular security audits should verify that no other similar vulnerabilities exist within the application's codebase. Security professionals should also consider deploying web application firewalls to monitor and filter suspicious traffic patterns that may indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date software versions and implementing robust security practices throughout the application lifecycle, aligning with ATT&CK technique T1566 for credential access through social engineering and T1059 for command and scripting interpreter execution. Organizations should establish incident response procedures to quickly address any exploitation attempts and conduct regular security training for administrators to recognize potential signs of compromise in their email systems.