CVE-2025-43781 is a reflected cross-site scripting (XSS) vulnerability identified in multiple versions of Liferay Portal and Liferay DXP, specifically versions 7.4.3.110 through 7.4.3.128, and various 2024 Q1, Q2, and Q3 releases of Liferay DXP. This vulnerability arises due to improper neutralization of user-supplied input during web page generation within the search bar portlet. An attacker can craft a malicious URL containing arbitrary JavaScript or HTML code that, when visited by a user, is reflected by the portal without proper sanitization or encoding. This allows the injected script to execute in the context of the victim’s browser session. The vulnerability is classified under CWE-79, indicating a failure to properly sanitize input leading to cross-site scripting. The CVSS 4.0 base score is 5.3 (medium severity), reflecting that the attack vector is network-based, requires no privileges, and no authentication, but does require user interaction (clicking a crafted URL). The impact on confidentiality and integrity is low to limited, with a limited impact on availability. No known exploits are currently reported in the wild, and no patches are linked in the provided data, suggesting that remediation may still be pending or recently released. The vulnerability affects a widely used enterprise portal platform that is often deployed for intranet, extranet, and public-facing web portals, making it a relevant concern for organizations relying on Liferay for content management and collaboration.

For European organizations using Liferay Portal or Liferay DXP, this vulnerability poses a risk primarily to end users who interact with the affected search bar portlet. Successful exploitation could lead to session hijacking, theft of sensitive cookies or credentials, unauthorized actions performed on behalf of users, or delivery of malicious payloads such as malware. This could compromise user privacy and organizational data integrity. Public-facing portals are particularly at risk, as attackers can lure users to malicious URLs via phishing or social engineering. Intranet deployments could also be affected if internal users access vulnerable components. The medium severity rating indicates a moderate risk, but the widespread use of Liferay in sectors such as government, finance, and healthcare across Europe raises concerns about potential targeted attacks. Additionally, the lack of required privileges or authentication lowers the barrier for exploitation. While no active exploits are known, the vulnerability could be weaponized in phishing campaigns or combined with other attack vectors to escalate impact.

European organizations should prioritize the following mitigations: 1) Immediate review and application of any available security patches or updates from Liferay once released, as no patch links were provided but vendors typically issue fixes promptly for XSS vulnerabilities. 2) Implement web application firewall (WAF) rules specifically targeting malicious payloads in URL parameters related to the search bar portlet to block reflected XSS attempts. 3) Conduct input validation and output encoding on all user-supplied data within customizations or extensions of Liferay portals to reduce exposure. 4) Educate users about the risks of clicking on suspicious URLs, especially those received via email or messaging platforms. 5) Employ Content Security Policy (CSP) headers to restrict execution of unauthorized scripts in browsers accessing the portal. 6) Monitor web server and application logs for unusual URL patterns or repeated attempts to exploit the search bar portlet. 7) For critical deployments, consider temporary disabling or restricting access to the vulnerable search bar portlet until patches are applied. These steps go beyond generic advice by focusing on immediate protective controls and user awareness tailored to the specific vulnerability vector.