CVE-2024-4150 is a reflected Cross-Site Scripting (XSS) vulnerability classified under CWE-79, found in the Simple Basic Contact Form plugin for WordPress developed by wpkube. The vulnerability exists in all versions up to and including 20221201 due to improper neutralization of input during web page generation. Specifically, the 'scf_email' parameter is not sufficiently sanitized or escaped before being reflected in the web page output. This flaw allows unauthenticated attackers to inject arbitrary JavaScript code into URLs that, when clicked by a victim, execute within the victim's browser context. The attack vector is network-based (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R). The scope is changed (S:C) because the vulnerability can affect the confidentiality and integrity of user data across security boundaries. The CVSS v3.1 base score is 6.1, indicating medium severity, with impacts on confidentiality and integrity but no impact on availability. Although no public exploits are currently known, the vulnerability poses a risk of session hijacking, credential theft, or content manipulation. The plugin’s widespread use in WordPress sites increases the potential attack surface, especially for sites that do not implement additional security controls such as Content Security Policy (CSP).

The primary impact of this vulnerability is the potential compromise of user confidentiality and integrity through execution of malicious scripts in the context of the affected website. Attackers can steal session cookies, perform actions on behalf of users, or deface website content. While availability is not impacted, the trustworthiness of affected websites can be undermined, leading to reputational damage and potential loss of user data. Organizations running WordPress sites with this plugin are at risk of targeted phishing or social engineering attacks that exploit this vulnerability. The risk is heightened for sites with high user interaction or those handling sensitive user information. The vulnerability’s requirement for user interaction limits automated exploitation but does not eliminate risk, especially in environments where users may be tricked into clicking malicious links via email or social media.

1. Immediately update the Simple Basic Contact Form plugin to a patched version once available from the vendor. 2. If an official patch is not yet released, implement manual input validation and output encoding on the 'scf_email' parameter to ensure all input is sanitized and escaped before rendering. 3. Deploy a robust Content Security Policy (CSP) to restrict the execution of unauthorized scripts on affected pages. 4. Educate users and administrators about the risks of clicking suspicious links and encourage cautious behavior. 5. Monitor web server logs for unusual URL patterns that may indicate exploitation attempts. 6. Consider using Web Application Firewalls (WAFs) with rules to detect and block reflected XSS payloads targeting this parameter. 7. Regularly audit and update all WordPress plugins to minimize exposure to known vulnerabilities. 8. Implement security headers such as X-XSS-Protection and HttpOnly cookies to reduce the impact of XSS attacks.