The phpMyFAQ 3.1.7 reflected Cross-Site Scripting (XSS) vulnerability (CVE-2022-3766) stems from inadequate input validation and output encoding of the 'search' parameter in the main index.php page. When a crafted GET request containing malicious JavaScript is sent to the vulnerable endpoint, the script is reflected in the HTTP response and executed by the victim's browser if they are authenticated. The exploit demonstrated involves injecting an 'onfocus' event handler that triggers a JavaScript alert, confirming the vulnerability. This attack vector allows adversaries to hijack user sessions, steal sensitive information stored or accessible via phpMyFAQ, manipulate displayed content, or perform actions on behalf of the user. The vulnerability requires no complex authentication bypass but does require the victim to be logged in, and no additional user interaction beyond visiting a malicious link is needed. The presence of exploit code in text format facilitates easy weaponization. Although no widespread exploitation is currently reported, the availability of proof-of-concept code and the common use of phpMyFAQ as an internal knowledge base increase the risk of targeted attacks. The vulnerability is mitigated by upgrading to phpMyFAQ 3.1.8 or later, which includes proper input sanitization and output encoding. Additional mitigations include deploying Web Application Firewalls, enforcing Content Security Policies, and monitoring for suspicious requests. Given phpMyFAQ’s role in managing internal and customer-facing FAQs, exploitation could lead to unauthorized disclosure of sensitive data and serve as a foothold for lateral movement within enterprise networks.

For European organizations, this reflected XSS vulnerability poses significant risks to the confidentiality and integrity of data and user sessions within phpMyFAQ installations. Attackers can hijack authenticated sessions, steal sensitive internal or customer support information, and manipulate content, potentially damaging organizational reputation and user trust. The risk is amplified in sectors governed by GDPR and other strict data protection laws, where unauthorized data exposure can result in heavy fines and legal repercussions. Since phpMyFAQ is often integrated with other internal systems or single sign-on solutions, exploitation could facilitate broader network intrusions or lateral movement, increasing operational risks. The ease of exploitation—requiring only a crafted URL and an authenticated victim—combined with publicly available exploit code, heightens the likelihood of phishing or social engineering campaigns targeting employees. Organizations with public-facing knowledge bases or large user bases face elevated risks of reputational damage, operational disruption, and compliance violations.

1. Immediately upgrade all phpMyFAQ installations to version 3.1.8 or later, where the reflected XSS vulnerability is patched. 2. Implement strict input validation and output encoding on all user-supplied data, especially the 'search' parameter, to prevent script injection. 3. Deploy and properly configure Web Application Firewalls (WAFs) to detect and block malicious payloads targeting this vulnerability pattern. 4. Enforce Content Security Policy (CSP) headers to restrict execution of unauthorized scripts in browsers. 5. Educate users and administrators to avoid clicking on suspicious links and implement multi-factor authentication to reduce session hijacking risks. 6. Regularly audit and monitor web application logs for unusual requests containing suspicious payloads indicative of attempted exploitation. 7. If immediate patching is not feasible, consider disabling or restricting access to the vulnerable search functionality or applying custom filtering rules at the web server or proxy level. 8. Conduct penetration testing and vulnerability scanning focused on XSS to proactively identify and remediate similar issues. 9. Review integration points with other internal systems to ensure that exploitation of phpMyFAQ does not provide broader network access.