CVE-2025-43787 is a stored cross-site scripting (XSS) vulnerability identified in Liferay Portal versions 7.4.0 through 7.4.3.132 and multiple versions of Liferay DXP from 2024.Q1.1 through 2025.Q3.0. This vulnerability arises due to improper neutralization of input during web page generation (CWE-79), specifically in the handling of organization site names. An authenticated remote attacker can inject malicious JavaScript code into the organization site name fields. Because the input is stored and later rendered without proper sanitization or escaping, the malicious script executes in the context of users who view the affected pages. The vulnerability requires the attacker to have some level of authenticated access (PR:L), but no elevated privileges are necessary. User interaction is required (UI:P) for the malicious payload to execute, typically when a user visits the compromised page. The CVSS 4.0 base score is 5.1, indicating a medium severity level. The attack vector is network-based (AV:N), with low attack complexity (AC:L), and no requirement for user authentication to exploit the vulnerability beyond the initial authenticated access. The impact affects confidentiality and integrity at a low level, with no direct impact on availability. No known exploits are currently reported in the wild. The vulnerability is significant because Liferay Portal and DXP are widely used enterprise content management and collaboration platforms, often hosting critical organizational data and services. Exploitation could lead to session hijacking, credential theft, or unauthorized actions performed on behalf of legitimate users, potentially compromising sensitive information or enabling further attacks within the affected environment.

For European organizations using Liferay Portal or DXP, this vulnerability poses a tangible risk to the confidentiality and integrity of their web applications and user data. Since Liferay is commonly deployed in sectors such as government, education, finance, and large enterprises across Europe, exploitation could lead to unauthorized access to sensitive information or manipulation of user sessions. The stored XSS nature means that once an attacker injects malicious scripts, all users accessing the affected pages are at risk, potentially leading to widespread compromise within an organization. This could result in reputational damage, regulatory non-compliance (notably with GDPR), and financial losses due to data breaches or operational disruptions. The requirement for authenticated access limits the attack surface somewhat, but insider threats or compromised credentials could facilitate exploitation. Additionally, the medium severity score suggests that while the vulnerability is not critical, it is sufficiently serious to warrant prompt remediation to prevent escalation or chaining with other vulnerabilities.

European organizations should implement the following specific mitigations: 1) Immediately update Liferay Portal and DXP installations to the latest patched versions once available from the vendor, as no patch links are currently provided but monitoring vendor advisories is critical. 2) Enforce strict input validation and output encoding on all user-supplied data, particularly organization site names, to prevent injection of malicious scripts. 3) Restrict and monitor authenticated user privileges to minimize the risk of malicious input from compromised or insider accounts. 4) Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. 5) Conduct regular security audits and penetration testing focused on XSS vulnerabilities in web applications. 6) Educate users to recognize suspicious behavior and report anomalies promptly. 7) Employ web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting Liferay-specific parameters. 8) Monitor logs for unusual activity related to organization site name changes or script injections. These measures, combined with timely patching, will reduce the risk of exploitation and limit potential damage.