CVE-2025-43740 is a stored cross-site scripting (XSS) vulnerability identified in multiple versions of the Liferay Portal and Liferay DXP products, specifically versions 7.4.3.120 through 7.4.3.132 and various 2024 and 2025 quarterly releases. The vulnerability resides in the message boards feature accessible via the web interface. An authenticated remote attacker with high privileges can inject malicious JavaScript code into the message boards, which is then stored and executed in the context of other users who view the affected content. This type of vulnerability is classified under CWE-79, indicating improper neutralization of input during web page generation. The CVSS v4.0 base score is 4.6, reflecting a medium severity level. The vector indicates network attack vector (AV:N), low attack complexity (AC:L), no authentication required (AT:N) but with high privileges (PR:H), user interaction required (UI:A), and low impact on confidentiality, integrity, and availability. The vulnerability does not appear to have known exploits in the wild as of the publication date. Stored XSS in a portal product like Liferay is significant because it can lead to session hijacking, credential theft, or unauthorized actions performed on behalf of users, especially in enterprise environments where Liferay is used for intranet portals, collaboration, and content management. The requirement for high privileges and user interaction somewhat limits the attack surface but does not eliminate risk, especially in environments with many users and complex role assignments.

For European organizations, the impact of this vulnerability can be considerable given Liferay's widespread use in government, education, and enterprise sectors across Europe. Successful exploitation could lead to unauthorized access to sensitive information, session hijacking, or the spread of malware within corporate intranets. The stored nature of the XSS means that malicious scripts persist and can affect multiple users over time, increasing the risk of data leakage or disruption of business processes. In regulated industries such as finance, healthcare, and public administration, this could also lead to compliance violations under GDPR and other data protection laws, potentially resulting in fines and reputational damage. The medium severity rating suggests that while the vulnerability is not trivial, it requires specific conditions (authenticated user with high privileges and user interaction) to exploit, which somewhat mitigates the risk but does not eliminate it. Organizations relying heavily on Liferay for internal communications or customer-facing portals should consider this a significant threat vector.

To mitigate this vulnerability, European organizations should: 1) Apply patches or updates from Liferay as soon as they become available, even though no patch links are currently provided, monitoring vendor advisories closely. 2) Restrict high-privilege user roles and enforce the principle of least privilege to limit the number of users who can exploit this vulnerability. 3) Implement robust input validation and output encoding on the message boards feature to neutralize malicious scripts, possibly using web application firewalls (WAFs) with custom rules targeting known XSS patterns. 4) Conduct regular security training for users with high privileges to recognize and avoid triggering malicious content. 5) Monitor logs and user activity for unusual behavior that could indicate exploitation attempts. 6) Consider deploying Content Security Policy (CSP) headers to reduce the impact of any injected scripts. 7) Perform regular security assessments and penetration testing focused on the message boards and other user-generated content features.