CVE-2025-43779 is a reflected Cross-Site Scripting (XSS) vulnerability identified in Liferay Portal versions 7.4.0 through 7.4.3.112 and Liferay DXP versions 2024.Q1.1 through 2024.Q1.18, as well as 7.4 GA through update 92. The vulnerability arises from improper sanitization of the _com_liferay_commerce_product_definitions_web_internal_portlet_CPDefinitionsPortlet_productTypeName parameter, which allows a remote attacker to inject malicious JavaScript code. This injected code is then reflected back and executed within the victim user's browser context. Notably, the vulnerability does not require authentication, user interaction, or privileges, making it accessible to unauthenticated remote attackers. The CVSS 4.0 base score is 6.9, indicating a medium severity level. The attack vector is network-based with low attack complexity and no privileges or user interaction required. The vulnerability impacts confidentiality and integrity to a limited extent, as the reflected XSS can be used to steal session tokens, perform actions on behalf of the user, or redirect users to malicious sites. However, it does not directly affect system availability. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability falls under CWE-79, which is a common web application security flaw related to improper input validation and output encoding, leading to script injection risks.

For European organizations using Liferay Portal or Liferay DXP within the affected versions, this vulnerability poses a significant risk to web application security. Exploitation could lead to session hijacking, unauthorized actions performed under the victim's credentials, and potential phishing attacks by injecting malicious scripts. This could result in data leakage, unauthorized access to sensitive information, and reputational damage. Given Liferay's popularity among enterprises for content management and digital experience platforms, especially in sectors like government, finance, and healthcare across Europe, the impact could be substantial. Attackers could target employees or customers via crafted URLs or links, exploiting the reflected XSS to compromise user accounts or implant malware. The lack of required authentication lowers the barrier for attackers, increasing the likelihood of exploitation attempts. While no active exploits are known, the medium severity and ease of exploitation warrant proactive mitigation to prevent potential attacks that could disrupt business operations or lead to regulatory non-compliance under GDPR due to data breaches.

European organizations should immediately assess their Liferay Portal and DXP deployments to identify affected versions. Until official patches are released, organizations should implement the following mitigations: 1) Employ Web Application Firewalls (WAFs) with custom rules to detect and block malicious payloads targeting the vulnerable parameter. 2) Apply strict Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers. 3) Conduct thorough input validation and output encoding on all user-supplied data, especially parameters related to productTypeName, to prevent script injection. 4) Educate users and administrators about the risks of clicking on suspicious links and encourage reporting of unusual behavior. 5) Monitor web server and application logs for unusual requests containing suspicious script patterns targeting the vulnerable parameter. 6) Plan and prioritize patching as soon as Liferay releases official updates addressing this vulnerability. 7) Consider isolating or restricting access to the affected portals if feasible, especially for high-risk user groups. These targeted measures go beyond generic advice by focusing on the specific vulnerable parameter and leveraging layered defenses to reduce attack surface and impact.