CVE-2024-58323 is a stored cross-site scripting vulnerability identified in Kentico Xperience, a popular web content management system. The vulnerability arises from improper neutralization of input during web page generation, specifically through the Checkbox form component that supports HTML input in the form builder. Attackers can inject malicious JavaScript code into the form data, which is then stored and later executed in the browsers of users who view the affected pages. This stored XSS can lead to unauthorized script execution, enabling attackers to hijack user sessions, steal sensitive information, perform actions on behalf of users, or deface websites. The vulnerability has a CVSS 4.0 base score of 5.1, reflecting medium severity, with an attack vector of network (remote exploitation), low attack complexity, no privileges required, but requiring user interaction (e.g., a user visiting a maliciously crafted page). The impact on confidentiality and integrity is low to limited, with no direct impact on availability. No known exploits have been reported in the wild as of the publication date. The vulnerability affects all versions listed as '0' (likely indicating all or unspecified versions), and no official patches have been linked yet. The root cause is insufficient input sanitization and output encoding in the Checkbox form component, which allows malicious HTML or script content to be stored and rendered unsafely. This vulnerability highlights the importance of rigorous input validation and output encoding in web applications, especially those that allow rich content input in user-facing forms.

For European organizations using Kentico Xperience, this vulnerability poses a risk primarily to web applications that utilize the Checkbox form component with HTML support. Exploitation could lead to session hijacking, unauthorized actions performed by users, theft of sensitive data such as authentication tokens or personal information, and potential website defacement. This can damage organizational reputation, lead to regulatory non-compliance (e.g., GDPR breaches if personal data is exposed), and result in financial losses. Public-facing websites and portals are particularly vulnerable, as attackers can lure users to interact with maliciously crafted forms or pages. The medium severity score suggests a moderate risk, but the ease of exploitation and potential for user impact means organizations should prioritize remediation. Since no known exploits are reported yet, proactive mitigation can prevent exploitation. The impact on availability is minimal, but confidentiality and integrity of user data and sessions are at risk. Organizations with high web traffic and sensitive user interactions are more exposed.

1. Immediately review and restrict the use of the Checkbox form component with HTML input in Kentico Xperience until a patch is available. 2. Implement strict input validation and output encoding on all form inputs, especially those allowing HTML content, to neutralize potentially malicious scripts. 3. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 4. Monitor web application logs for unusual input patterns or repeated injection attempts targeting form components. 5. Educate web developers and administrators on secure coding practices related to input handling and XSS prevention. 6. Once Kentico releases an official patch or update addressing CVE-2024-58323, prioritize its deployment in all affected environments. 7. Conduct penetration testing focused on XSS vulnerabilities in web forms to identify any residual or similar issues. 8. Consider implementing web application firewalls (WAF) with rules to detect and block XSS payloads targeting form inputs. 9. Limit user privileges where possible to reduce the impact of potential exploitation. 10. Regularly update and audit third-party components and plugins integrated with Kentico Xperience to ensure no additional vulnerabilities exist.