CVE-2020-8594: 
WordPress vulnerability analysis and mitigation

The Ninja Forms plugin version 3.4.22 for WordPress contains Multiple Stored Cross-Site Scripting (XSS) vulnerabilities. The vulnerability was discovered on February 3, 2020, and affects several parameters in the plugin's settings page including ninja_forms[recaptcha_site_key], ninja_forms[recaptcha_secret_key], ninja_forms[recaptcha_lang], and ninja_forms[date_format] (Spider Security).

The vulnerability exists in the administrative section of the Ninja Forms WordPress plugin where multiple parameters are susceptible to Stored XSS attacks. The affected parameters can be exploited by injecting malicious scripts that are stored on the server and executed when an administrator accesses the affected pages. The vulnerability has been assigned a CVSS v3.1 base score of 5.4 (Medium) with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N (NVD).

If exploited, this vulnerability could allow attackers to hijack administrative cookies, potentially leading to unauthorized access to the WordPress admin panel. The risk is particularly significant when combined with phishing campaigns, as it could compromise website administrator accounts (Spider Security).

The vulnerability has been patched in version 3.4.23 of the Ninja Forms plugin. Site administrators are strongly advised to update to this version or later. Additionally, implementing Content Security Policy (CSP) headers and maintaining regular plugin updates can help prevent such vulnerabilities from being exploited (Spider Security).