CVE-2022-42117 is a Cross-site Scripting (XSS) vulnerability identified in the Frontend Taglib module of Liferay Portal versions 7.3.2 through 7.4.3.16, and Liferay DXP versions 7.3 before update 6 and 7.4 before update 17. This vulnerability allows remote attackers to inject arbitrary web scripts or HTML into the affected application. The vulnerability arises due to insufficient input sanitization or output encoding in the Frontend Taglib module, which is responsible for rendering dynamic content in Liferay portals. Exploiting this flaw requires no privileges (PR:N) but does require user interaction (UI:R), such as tricking a user into clicking a crafted link or visiting a malicious page. The vulnerability has a CVSS v3.1 base score of 6.1, indicating a medium severity level. The attack vector is network-based (AV:N), with low attack complexity (AC:L), and it impacts confidentiality and integrity with a scope change (S:C), but does not affect availability. While no known exploits are currently reported in the wild, the vulnerability poses a risk of session hijacking, credential theft, or unauthorized actions performed in the context of the victim's session. Liferay Portal and DXP are widely used enterprise content management and digital experience platforms, often deployed by organizations for intranet portals, customer-facing websites, and collaboration platforms. The Frontend Taglib module is a core component that dynamically generates web content, making this vulnerability a significant concern for any organization using affected versions. Since the vulnerability requires user interaction, social engineering or phishing campaigns could be used to exploit it. The lack of a publicly available patch link in the provided data suggests organizations should verify with Liferay for official updates or mitigations.

For European organizations using Liferay Portal or DXP, this vulnerability could lead to unauthorized disclosure of sensitive information, such as session tokens or personal data, through injected scripts. Attackers could leverage this to impersonate users, escalate privileges, or conduct further attacks within the network. The integrity of web content could be compromised, damaging organizational reputation and trust. Given the widespread use of Liferay in sectors such as government, finance, and healthcare across Europe, exploitation could disrupt critical services or expose confidential data. The medium severity rating indicates a moderate risk, but the potential for targeted phishing attacks increases the threat level. Additionally, the scope change in the CVSS vector means the vulnerability could affect components beyond the initially vulnerable module, potentially impacting other integrated systems. Organizations with public-facing Liferay portals are particularly at risk, as attackers can deliver malicious payloads remotely without authentication. The absence of known exploits in the wild reduces immediate risk but does not eliminate it, especially as threat actors may develop exploits over time.

European organizations should immediately verify the version of Liferay Portal or DXP in use and prioritize upgrading to versions beyond 7.4.3.16 for Portal and applying updates 6 and 17 or later for DXP 7.3 and 7.4 respectively, once available. In the absence of official patches, organizations should implement strict input validation and output encoding on all user-supplied data rendered by the Frontend Taglib module. Deploying Web Application Firewalls (WAFs) with custom rules to detect and block typical XSS payloads targeting Liferay can provide interim protection. Security teams should conduct thorough code reviews and penetration testing focusing on the Frontend Taglib module and related components. User awareness training to recognize phishing attempts can reduce the risk of successful exploitation requiring user interaction. Monitoring web logs for unusual script injection attempts or anomalous user behavior can help detect exploitation attempts early. Additionally, organizations should isolate critical Liferay instances behind VPNs or restrict access to trusted networks where possible to reduce exposure. Finally, subscribing to Liferay security advisories and threat intelligence feeds will ensure timely awareness of patches and emerging threats.