CVE-2025-49861 is a Stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the Timur Kamaev Kama Click Counter product up to version 4.0.3. The vulnerability arises due to improper neutralization of input during web page generation, allowing malicious scripts to be stored and subsequently executed in the context of users visiting the affected web pages. This type of vulnerability enables attackers to inject arbitrary JavaScript code that can execute within the victim's browser, potentially leading to session hijacking, credential theft, defacement, or redirection to malicious sites. The CVSS 3.1 base score is 6.5, indicating a medium severity level. The vector string (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L) reveals that the attack can be performed remotely over the network with low attack complexity, requires low privileges, and user interaction is necessary. The vulnerability impacts confidentiality, integrity, and availability to a limited extent, with a scope change indicating that the vulnerability affects components beyond the initially vulnerable component. No patches or known exploits in the wild have been reported as of the publication date (June 17, 2025). The vulnerability is significant because stored XSS can persistently affect multiple users and can be leveraged in targeted attacks against organizations using the Kama Click Counter, a web analytics tool embedded in websites to track user clicks.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on the Kama Click Counter for web analytics and user interaction tracking. Exploitation could lead to unauthorized access to sensitive user data, session hijacking, and manipulation of website content, undermining user trust and potentially violating data protection regulations such as GDPR. The persistent nature of stored XSS increases the risk of widespread compromise across an organization's user base. Additionally, the integrity of web analytics data could be compromised, leading to inaccurate business insights and decision-making. Organizations in sectors with high regulatory scrutiny, such as finance, healthcare, and e-commerce, may face legal and reputational consequences if exploited. The requirement for low privileges and user interaction lowers the barrier for attackers, increasing the likelihood of successful exploitation in targeted phishing or social engineering campaigns.

To mitigate this vulnerability, European organizations should implement the following specific measures: 1) Immediately audit all instances of Kama Click Counter on their websites and identify versions up to 4.0.3. 2) Since no official patches are currently available, apply virtual patching via Web Application Firewalls (WAFs) configured to detect and block typical XSS payloads targeting the vulnerable input fields. 3) Implement strict Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of potential XSS payloads. 4) Sanitize and validate all user inputs on the server side, ensuring that any data rendered on web pages is properly encoded to neutralize script injection attempts. 5) Educate web developers and administrators on secure coding practices, emphasizing the importance of input validation and output encoding. 6) Monitor web traffic and logs for unusual activity indicative of exploitation attempts, including repeated input of suspicious scripts or anomalous user behavior. 7) Plan for an upgrade or replacement of the Kama Click Counter component once a patched version is released, or consider alternative analytics tools with a stronger security posture. 8) Conduct regular security assessments and penetration testing focusing on web application vulnerabilities, including XSS.