CVE-2025-62951 is a stored Cross-site Scripting (XSS) vulnerability identified in the icc0rz Interactive Content – H5P plugin, a widely used tool for creating interactive web content, particularly in educational platforms. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, allowing malicious scripts to be stored and later executed in the browsers of other users who access the affected content. This stored XSS can be exploited by an attacker with at least limited privileges (PR:L) and requires user interaction (UI:R), such as viewing the malicious content. The CVSS vector indicates network attack vector (AV:N), low attack complexity (AC:L), partial confidentiality, integrity, and availability impacts (C:L/I:L/A:L), and a scope change (S:C), meaning the vulnerability affects components beyond the initially vulnerable module. Although no known exploits are currently reported in the wild, the potential for phishing, session hijacking, or unauthorized actions exists. The vulnerability affects all versions of Interactive Content – H5P up to 1.16.0, with no patch links currently provided, indicating that remediation may require vendor updates or manual mitigations. Given H5P's popularity in European educational institutions and e-learning platforms, this vulnerability poses a tangible risk to user data and platform integrity.

For European organizations, particularly those in education, e-learning, and content delivery sectors, this vulnerability could lead to unauthorized script execution in users' browsers, resulting in data leakage, session hijacking, or manipulation of content integrity. Confidential information such as user credentials or personal data could be exposed, violating GDPR and other privacy regulations. The partial availability impact could disrupt content delivery or platform functionality, affecting user experience and trust. Since exploitation requires some level of authentication and user interaction, internal users or trusted contributors could be targeted to escalate attacks. The scope change suggests that the vulnerability might affect other integrated components or services, potentially increasing the attack surface. Organizations relying heavily on H5P for interactive content creation and delivery in Europe must consider the risk to their users and infrastructure, especially given the regulatory environment emphasizing data protection and security.

1. Monitor for official patches or updates from the icc0rz H5P project and apply them promptly once available. 2. Implement strict input validation and output encoding on all user-generated content fields to prevent injection of malicious scripts. 3. Deploy a robust Content Security Policy (CSP) to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 4. Limit user privileges to the minimum necessary, especially for content contributors, to reduce the risk of malicious input. 5. Conduct regular security audits and penetration testing focusing on interactive content modules. 6. Educate users and administrators about the risks of XSS and encourage cautious behavior when interacting with user-generated content. 7. Consider isolating or sandboxing interactive content components to contain potential script execution. 8. Utilize web application firewalls (WAFs) with rules tailored to detect and block XSS payloads targeting H5P content. 9. Review and enhance logging and monitoring to detect suspicious activities related to content injection or script execution.