CVE-2025-62240 is a cross-site scripting (XSS) vulnerability classified under CWE-79 that affects Liferay Portal versions 7.4.3.35 through 7.4.3.111 and multiple Liferay DXP versions including 2023.Q4.0 through 2023.Q4.5, 2023.Q3.1 through 2023.Q3.7, 7.4 update 35 through update 92, and 7.3 update 25 through update 36. The vulnerability arises from improper neutralization of user-supplied input during web page generation, specifically in the handling of Calendar event user fields such as First Name, Middle Name, and Last Name. Attackers can craft malicious payloads that, when injected into these fields, execute arbitrary JavaScript or HTML in the context of other users viewing the affected pages. This can lead to session hijacking, credential theft, or unauthorized actions performed on behalf of the victim. The CVSS 4.0 base score is 4.8 (medium), reflecting network attack vector, low attack complexity, no privileges required, but requiring user interaction and limited impact on confidentiality and integrity. No known exploits are currently in the wild, and no patches have been officially released, though the vendor has acknowledged the issue. The vulnerability affects both public-facing and internal portals, making it a significant concern for organizations relying on Liferay for collaboration or content management.

For European organizations, this vulnerability poses risks primarily to the confidentiality and integrity of user sessions and data. Exploitation could allow attackers to execute malicious scripts in the browsers of authenticated users, potentially leading to session hijacking, theft of sensitive information, or unauthorized actions within the portal environment. Organizations using Liferay for customer portals, intranets, or collaboration platforms could face data breaches or operational disruptions. The impact is heightened in sectors with strict data protection regulations such as GDPR, where unauthorized data access or leakage can result in significant legal and financial penalties. Additionally, the presence of this vulnerability in multiple Liferay versions increases the attack surface, especially for organizations that delay patching or use customized deployments. The lack of known exploits currently provides a window for proactive mitigation, but the risk of future exploitation remains. The vulnerability could also be leveraged as a foothold for more advanced attacks targeting European digital infrastructure.

1. Immediately audit all Liferay Portal and DXP instances to identify affected versions and instances where Calendar event user fields are enabled. 2. Implement strict input validation and sanitization on user-supplied fields, especially First Name, Middle Name, and Last Name, to block or encode potentially malicious scripts. 3. Apply output encoding on all user-generated content rendered in web pages to prevent script execution. 4. Restrict permissions to modify Calendar event user fields to trusted users only, reducing the risk of malicious input. 5. Monitor web application logs and user activity for unusual patterns indicative of XSS exploitation attempts. 6. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 7. Engage with Liferay support channels to obtain and apply official patches or updates as soon as they become available. 8. Educate users about the risks of interacting with suspicious links or content within the portal. 9. Consider deploying web application firewalls (WAF) with rules tuned to detect and block XSS payloads targeting Liferay. 10. Plan for regular security assessments and penetration testing focused on input validation and XSS vulnerabilities in Liferay environments.