CVE-2025-43742 is a reflected 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.Q1.3, including 7.4 GA through update 92. The vulnerability arises due to improper neutralization of user-supplied input during web page generation, specifically in the handling of friendly URLs. This flaw allows a remote attacker with no authentication or user interaction required to inject malicious JavaScript code into web content. When a victim accesses a crafted URL, the injected script executes in the context of the victim's browser, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the network attack vector, low attack complexity, no privileges or user interaction needed, and limited impact on confidentiality and integrity but no impact on availability. The vulnerability is classified under CWE-79, which covers improper neutralization of input leading to XSS. No known exploits in the wild have been reported yet, and no official patches have been linked in the provided data. Given the widespread use of Liferay Portal and DXP in enterprise web portals, this vulnerability poses a significant risk if left unmitigated, especially for public-facing portals that accept user input in URLs.

For European organizations, the impact of CVE-2025-43742 can be substantial, particularly for those relying on Liferay Portal or DXP for customer-facing websites, intranets, or digital services. Successful exploitation could allow attackers to execute arbitrary scripts in users' browsers, leading to theft of session cookies, user credentials, or sensitive data. This could facilitate further attacks such as account takeover, unauthorized access to internal resources, or distribution of malware. The reflected nature of the XSS means phishing campaigns could be enhanced by embedding malicious links that appear legitimate. Organizations in sectors such as finance, government, healthcare, and e-commerce, which often use Liferay for their portals, may face reputational damage, regulatory penalties under GDPR if personal data is compromised, and operational disruptions. The medium severity score indicates a moderate but non-trivial risk that should be addressed promptly to prevent exploitation.

1. Immediate mitigation should include implementing strict input validation and output encoding on all user-supplied data, especially in URL parameters and friendly URL handlers within Liferay Portal and DXP. 2. Deploy Web Application Firewalls (WAFs) with rules tailored to detect and block reflected XSS payloads targeting Liferay endpoints. 3. Monitor web server and application logs for unusual or suspicious URL patterns that may indicate attempted exploitation. 4. Restrict or sanitize user-generated content and URL parameters to disallow script tags or event handlers. 5. Apply the latest security updates and patches from Liferay as soon as they become available; if patches are not yet released, consider temporary workarounds such as disabling or restricting affected modules or features. 6. Educate users and administrators about the risks of clicking untrusted links and encourage the use of security headers like Content Security Policy (CSP) to reduce the impact of XSS. 7. Conduct thorough security testing and code reviews focusing on input handling in the portal environment to identify and remediate similar vulnerabilities proactively.