CVE-2025-63520 is a Cross Site Scripting (XSS) vulnerability identified in FeehiCMS version 2.1.1. The vulnerability exists in the User Update function, specifically via the 'id' parameter in the URL (?r=user%2Fupdate). An attacker can craft a malicious payload that, when processed by the vulnerable parameter, injects executable JavaScript into the web page viewed by other users or administrators. This type of vulnerability exploits insufficient input validation and output encoding, allowing arbitrary script execution in the victim's browser context. The impact of such an XSS flaw includes theft of session cookies, redirection to malicious sites, or execution of unauthorized actions on behalf of the user. FeehiCMS is a content management system used primarily in web applications to manage content and user data. Although the affected versions are not explicitly detailed beyond 2.1.1, the vulnerability is confirmed in that release. No CVSS score has been assigned yet, and no public exploits are currently known, indicating it may be newly discovered or not yet weaponized. The vulnerability was reserved in late October 2025 and published in December 2025. The lack of patches or mitigation links suggests that users should proactively apply input validation and output encoding best practices or await vendor updates. This vulnerability requires no authentication to exploit, as it targets a parameter in a user update function accessible via URL, increasing its risk profile. XSS vulnerabilities are common attack vectors for web applications and can be leveraged in targeted attacks or broad phishing campaigns.

For European organizations, the impact of this XSS vulnerability can be significant, particularly for those using FeehiCMS 2.1.1 in public-facing web applications. Successful exploitation can lead to compromise of user sessions, unauthorized access to sensitive information, and potential defacement or manipulation of website content. This can damage organizational reputation, lead to data breaches involving personal data protected under GDPR, and cause operational disruptions. Sectors such as government, education, and small to medium enterprises that rely on FeehiCMS for content management are particularly vulnerable. The ease of exploitation without authentication means attackers can launch attacks remotely and at scale, increasing the risk of widespread impact. Additionally, the lack of known exploits currently provides a window for mitigation before active exploitation occurs. However, once weaponized, the vulnerability could facilitate phishing, credential theft, and lateral movement within compromised networks. The impact on confidentiality and integrity is high, while availability impact is generally low unless combined with other attack vectors.

To mitigate CVE-2025-63520, organizations should immediately review and harden the input validation mechanisms for the 'id' parameter in the User Update function of FeehiCMS. Implement strict server-side input sanitization to reject or neutralize any script tags or suspicious characters. Employ output encoding techniques to ensure that any user-supplied data rendered in the browser is safely escaped. Monitor web application logs for unusual or malformed requests targeting the user update endpoint. If possible, restrict access to the user update functionality to authenticated and authorized users only, adding an additional security layer. Organizations should also subscribe to vendor advisories for FeehiCMS to apply official patches once available. Employ Content Security Policy (CSP) headers to reduce the impact of potential XSS attacks by restricting script execution sources. Conduct regular security assessments and penetration tests focusing on web application vulnerabilities. Finally, educate web administrators and developers on secure coding practices to prevent similar vulnerabilities in the future.