CVE-2025-43783 is a reflected Cross-Site Scripting (XSS) vulnerability identified in multiple versions of the Liferay Portal and Liferay DXP products. Specifically, it affects Liferay Portal versions 7.4.3.73 through 7.4.3.128 and Liferay DXP versions 2024.Q1.1 through 2024.Q3.1, including various quarterly updates. The vulnerability arises from improper neutralization of user-supplied input during web page generation, classified under CWE-79. Attackers can exploit this flaw by sending crafted requests to the /c/portal/comment/discussion/get_editor endpoint, which fails to adequately sanitize input parameters. This allows injection of arbitrary HTML or JavaScript code that is reflected back to the victim's browser. The vulnerability is exploitable remotely without authentication and requires user interaction (e.g., clicking a malicious link). The CVSS v4.0 base score is 5.1 (medium severity), reflecting network attack vector, low attack complexity, no privileges required, but requiring user interaction and causing low impact on confidentiality and integrity. No known exploits are currently reported in the wild. The vulnerability could enable attackers to perform actions such as session hijacking, defacement, or redirecting users to malicious sites, depending on the victim's browser and security posture. Since the flaw is in a widely used enterprise portal platform, it poses a risk to web applications relying on Liferay for content management and collaboration.

For European organizations, this vulnerability presents a moderate risk primarily to web-facing portals and intranet sites built on affected Liferay versions. Exploitation could lead to theft of session cookies, enabling unauthorized access to user accounts, or execution of malicious scripts in the context of trusted domains. This can compromise user data confidentiality and integrity, potentially leading to data breaches or unauthorized actions within enterprise systems. Given Liferay's adoption in sectors such as government, education, and large enterprises across Europe, successful exploitation could disrupt business operations, damage reputation, and lead to regulatory non-compliance under GDPR if personal data is exposed. The requirement for user interaction limits automated mass exploitation but targeted phishing or social engineering campaigns could leverage this vulnerability effectively. The lack of known active exploits currently reduces immediate risk but does not preclude future attacks once exploit code becomes available.

Organizations should prioritize upgrading Liferay Portal and DXP installations to versions beyond those affected, as vendors typically release patches addressing such vulnerabilities. In absence of immediate patches, implementing Web Application Firewall (WAF) rules to detect and block suspicious input patterns targeting the /c/portal/comment/discussion/get_editor endpoint can reduce risk. Input validation and output encoding should be enforced at the application layer to neutralize malicious scripts. Security teams should conduct thorough code reviews and penetration testing focusing on XSS vectors in custom Liferay modules or themes. User awareness training to recognize phishing attempts can mitigate the risk of user interaction exploitation. Additionally, monitoring web server logs for unusual requests to the vulnerable endpoint can help detect attempted exploitation. Employing Content Security Policy (CSP) headers can limit the impact of injected scripts by restricting script execution sources.