CVE-2025-56429 is a Cross Site Scripting (XSS) vulnerability classified under CWE-79 affecting Fearless Geek Media's FearlessCMS, version 0.0.2-15. The vulnerability resides in the login.php component, where insufficient input sanitization allows an attacker to inject malicious scripts that execute in the victim's browser context. This flaw enables attackers to steal sensitive information such as session tokens, cookies, or other credentials by tricking users into interacting with crafted URLs or forms. The vulnerability has a CVSS v3.1 base score of 6.1, indicating medium severity, with an attack vector of network (remote), low attack complexity, no privileges required, but requiring user interaction. The scope is changed, meaning the vulnerability can affect components beyond the vulnerable module. The impact affects confidentiality and integrity but not availability. There are no known public exploits or patches available at the time of publication (December 2025). The vulnerability was reserved in August 2025 and published in December 2025. Given the nature of XSS, exploitation typically involves social engineering to lure users into clicking malicious links or submitting crafted input. FearlessCMS is a niche content management system, and the affected version is relatively early (0.0.2-15), which may limit exposure but also indicates potential immaturity in security controls. The lack of patches necessitates immediate mitigation strategies to prevent exploitation.

For European organizations using FearlessCMS, this vulnerability poses a risk of sensitive data disclosure through session hijacking or credential theft, potentially leading to unauthorized access or data breaches. The confidentiality and integrity of user data can be compromised, especially for organizations relying on the CMS for authentication or sensitive content management. While availability is not directly impacted, the reputational damage and compliance risks (e.g., GDPR violations due to data leakage) can be significant. Organizations in sectors such as government, finance, healthcare, or media that use FearlessCMS for public-facing or internal portals are particularly vulnerable. The requirement for user interaction means phishing or social engineering campaigns could amplify the threat. The absence of known exploits reduces immediate risk but does not eliminate it, as attackers may develop exploits rapidly after disclosure. The medium severity score suggests prioritizing remediation but not an emergency response unless active exploitation is detected.

1. Implement strict input validation and output encoding on all user-supplied data in the login.php component to prevent script injection. 2. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts within the CMS environment. 3. Deploy Web Application Firewalls (WAFs) configured to detect and block common XSS attack patterns targeting the login page. 4. Educate users and administrators about phishing and social engineering risks associated with XSS attacks to reduce successful exploitation. 5. Monitor web server and application logs for unusual requests or patterns indicative of attempted XSS exploitation. 6. If possible, isolate the CMS environment or restrict access to trusted networks until a patch or update is available. 7. Engage with Fearless Geek Media for updates or patches and apply them promptly once released. 8. Conduct regular security assessments and penetration testing focusing on input handling and authentication components. 9. Consider implementing multi-factor authentication (MFA) to reduce the impact of stolen credentials resulting from XSS attacks.