CVE-2025-43753 is a reflected Cross-Site Scripting (XSS) vulnerability identified in multiple versions of Liferay Portal and Liferay DXP, specifically versions 7.4.3.32 through 7.4.3.132 and various quarterly releases of Liferay DXP from 2024.Q1.1 through 2025.Q1.7. The vulnerability arises due to improper neutralization of input during web page generation (CWE-79), allowing a remote authenticated user to inject malicious JavaScript code into the embedded message field within a form container. This injection occurs when user-supplied input is not correctly sanitized or encoded before being reflected back in the web page, enabling the execution of arbitrary scripts in the context of the victim's browser session. The vulnerability requires the attacker to be authenticated with high privileges (as indicated by the CVSS vector's PR:H), and no user interaction is needed once the malicious payload is delivered. The CVSS v4.0 base score is 2.1, reflecting a low severity primarily due to the high attack complexity and requirement for authenticated access. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. The vulnerability could be leveraged to perform actions such as session hijacking, defacement, or redirecting users to malicious sites, but the limited scope and conditions reduce its immediate risk profile.

For European organizations using Liferay Portal or Liferay DXP, this vulnerability could lead to targeted attacks where authenticated users with elevated privileges inject malicious scripts, potentially compromising session integrity and user data confidentiality within the portal environment. Given that Liferay is widely used for enterprise intranet portals, customer-facing websites, and digital experience platforms, exploitation could disrupt business operations, erode user trust, and expose sensitive corporate information. However, since exploitation requires authenticated access with high privileges, the risk is somewhat contained within internal or trusted user bases. Nonetheless, insider threats or compromised credentials could amplify the impact. Additionally, the reflected XSS could be used as a stepping stone for more sophisticated attacks, such as privilege escalation or lateral movement within the network. The low CVSS score suggests limited direct impact on availability or system integrity, but confidentiality and integrity of user sessions and data could be affected. European organizations with compliance requirements around data protection (e.g., GDPR) must consider the potential for data leakage or unauthorized access resulting from this vulnerability.

To mitigate CVE-2025-43753, European organizations should implement the following specific measures: 1) Apply input validation and output encoding rigorously on all user-supplied data, especially within the embedded message fields of Liferay forms, to neutralize potentially malicious scripts. 2) Restrict high-privilege user accounts and enforce the principle of least privilege to minimize the pool of users capable of exploiting this vulnerability. 3) Monitor and audit user activities within the portal to detect anomalous behavior indicative of XSS exploitation attempts. 4) Employ Web Application Firewalls (WAFs) with custom rules to detect and block reflected XSS payloads targeting Liferay-specific parameters. 5) Stay updated with Liferay vendor advisories and apply security patches promptly once released. 6) Educate authenticated users about phishing and social engineering risks that could lead to credential compromise, thereby reducing the likelihood of an attacker gaining the necessary privileges. 7) Consider implementing Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts within the portal environment. These targeted actions go beyond generic advice by focusing on the specific context and exploitation conditions of this vulnerability.