CVE-2022-3765 is a high-severity stored Cross-site Scripting (XSS) vulnerability identified in the thorsten/phpmyfaq project, a PHP-based FAQ management system. The vulnerability arises from improper neutralization of input during web page generation (CWE-79), allowing an attacker to inject malicious scripts that are stored on the server and subsequently executed in the browsers of users who access the affected pages. This flaw exists in versions prior to 3.1.8 of phpmyfaq, although the exact affected versions are unspecified. The vulnerability is remotely exploitable without authentication (AV:N/AC:L/PR:N/UI:N), meaning an attacker can trigger it over the network without any privileges or user interaction. The CVSS v3.0 base score is 8.2, reflecting a high impact primarily on confidentiality (C:H), with limited impact on integrity (I:L) and no impact on availability (A:N). The vulnerability allows an attacker to steal sensitive information such as session cookies, perform actions on behalf of users, or deliver further malware payloads by injecting malicious JavaScript into FAQ entries or other input fields that are rendered without proper sanitization. No known public exploits have been reported yet, but the presence of this vulnerability in a widely used open-source FAQ system poses a significant risk, especially for organizations that rely on phpmyfaq for customer support or internal knowledge bases. The lack of a provided patch link suggests users must upgrade to version 3.1.8 or later, where the issue is presumably fixed, or apply manual input sanitization and output encoding as interim measures.

For European organizations, the impact of CVE-2022-3765 can be substantial, particularly for those using phpmyfaq to manage customer-facing or internal knowledge bases. Exploitation can lead to theft of user credentials, session hijacking, and unauthorized actions performed under the guise of legitimate users, potentially compromising sensitive business or personal data. This can result in reputational damage, regulatory non-compliance (e.g., GDPR violations due to data leakage), and operational disruptions. Since the vulnerability requires no authentication or user interaction, it can be exploited at scale by remote attackers scanning for vulnerable phpmyfaq instances. Organizations in sectors with high data sensitivity such as finance, healthcare, and government are at elevated risk. Additionally, the stored XSS can be used as a pivot point for further attacks within the network, increasing the overall threat surface. The absence of known exploits in the wild currently reduces immediate risk but does not diminish the urgency of remediation given the ease of exploitation and high confidentiality impact.

1. Upgrade phpmyfaq installations to version 3.1.8 or later, where the vulnerability is addressed. 2. If immediate upgrade is not feasible, implement strict input validation and output encoding on all user-supplied content fields, especially those rendered in HTML contexts. Use well-established libraries or frameworks for sanitization to prevent injection of executable scripts. 3. Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and reduce the impact of potential XSS payloads. 4. Conduct thorough code reviews and penetration testing focused on input handling and output rendering in phpmyfaq customizations or integrations. 5. Monitor web server logs and application behavior for unusual requests or script injections indicative of attempted exploitation. 6. Educate administrators and users about the risks of XSS and encourage prompt reporting of suspicious behavior. 7. Consider deploying Web Application Firewalls (WAFs) with rules targeting common XSS attack patterns as an additional protective layer.