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 and e-learning environments. The vulnerability stems from improper neutralization of user-supplied input during the generation of web pages, allowing malicious scripts to be stored persistently within the content. When a victim accesses the compromised interactive content, the malicious script executes in their browser context. This can lead to a range of attacks including session hijacking, credential theft, unauthorized actions on behalf of the user, and potential spread of malware. The vulnerability affects all versions up to and including 1.16.0, with no CVSS score assigned yet and no known exploits in the wild at the time of publication. Exploitation does not require authentication or user interaction beyond viewing the content, increasing the risk profile. The lack of proper input sanitization and output encoding in the plugin's content rendering process is the root cause. Given H5P's popularity in Europe for interactive educational content, this vulnerability poses a significant risk to institutions relying on it for digital learning platforms. The absence of a patch link suggests that remediation may require vendor updates or manual mitigation steps. Organizations should monitor for updates and apply security best practices to mitigate risk.

The impact of CVE-2025-62951 on European organizations is considerable, especially for educational institutions, e-learning providers, and any organizations using H5P for interactive web content. Successful exploitation can compromise user confidentiality by stealing session cookies or credentials, leading to unauthorized access to sensitive information. Integrity is at risk as attackers can manipulate content or perform actions on behalf of users, potentially disrupting educational processes or spreading misinformation. Availability could be indirectly affected if attacks lead to account lockouts or platform instability. The stored nature of the XSS means that multiple users can be affected once malicious content is injected, amplifying the damage. Given the widespread adoption of H5P in Europe, particularly in countries with strong digital education initiatives, the threat could impact a large user base. Additionally, the ease of exploitation without authentication or user interaction increases the likelihood of successful attacks. This vulnerability could also be leveraged as a foothold for further attacks within organizational networks, increasing overall risk.

To mitigate CVE-2025-62951, European organizations should: 1) Monitor the icc0rz vendor and H5P community for official patches and apply updates promptly once available. 2) Implement strict input validation and output encoding on all user-generated content within H5P to prevent injection of malicious scripts. 3) Deploy Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts and reduce the impact of XSS attacks. 4) Conduct regular security audits and code reviews of custom H5P content or integrations to identify and remediate unsafe coding practices. 5) Educate content creators and administrators about the risks of injecting untrusted content and enforce least privilege principles for content editing. 6) Use web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting H5P endpoints. 7) Monitor logs and user activity for signs of exploitation attempts or unusual behavior. 8) Consider sandboxing or isolating interactive content environments to limit the scope of potential compromise. These measures, combined with timely patching, will significantly reduce the risk posed by this vulnerability.