CVE-2025-43791 is a medium-severity cross-site scripting (XSS) vulnerability affecting multiple versions of Liferay Portal and Liferay DXP products, specifically versions 7.3.0 through 7.4.3.111 and various 2023 Q3 and Q4 releases. The vulnerability arises from improper neutralization of input during web page generation (CWE-79), allowing remote attackers to inject arbitrary web scripts or HTML. This injection occurs via crafted payloads submitted into "Rich Text" type fields within several components: web content structures, Documents and Media Document Types, and custom assets that utilize the Data Engine's Rich Text module. Exploitation does not require authentication but does require user interaction, such as a victim visiting a maliciously crafted page or content. The CVSS 4.0 base score is 4.8, reflecting a medium severity level due to the 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 reported in the wild. The vulnerability could allow attackers to execute arbitrary JavaScript in the context of the victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions within the affected portal environment. The lack of patches at the time of reporting indicates the need for immediate attention from administrators.

For European organizations using Liferay Portal or Liferay DXP, this vulnerability poses a risk primarily to web application security and user trust. Successful exploitation could lead to theft of user credentials, session tokens, or unauthorized actions performed on behalf of legitimate users, potentially compromising sensitive business data or internal communications. Given Liferay's popularity as a portal and content management platform in sectors such as government, finance, and education across Europe, exploitation could disrupt critical services or lead to data breaches. The medium severity suggests the impact is significant but not catastrophic; however, the widespread use of rich text fields in content management increases the attack surface. Additionally, organizations with high compliance requirements under GDPR must consider the reputational and regulatory consequences of any data leakage or unauthorized access resulting from this vulnerability.

To mitigate CVE-2025-43791, European organizations should: 1) Immediately audit all Liferay Portal and DXP instances to identify affected versions and prioritize upgrades once patches are released. 2) Implement strict input validation and output encoding on all rich text fields, especially those exposed to untrusted users or contributors, to neutralize malicious scripts. 3) Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts within the portal environment. 4) Limit user permissions to restrict who can create or edit rich text content, minimizing the risk of malicious payload injection. 5) Monitor web logs and user activity for signs of XSS exploitation attempts or unusual behavior. 6) Educate users about the risks of interacting with untrusted content and encourage cautious browsing practices within the portal. 7) Consider deploying web application firewalls (WAFs) with rules tuned to detect and block XSS payloads targeting Liferay components. These measures, combined with timely patching, will reduce the risk of exploitation.