CVE-2025-43817 is a reflected cross-site scripting vulnerability classified under CWE-79, affecting Liferay Portal versions 7.4.3.74 through 7.4.3.111 and multiple Liferay DXP versions from 2023.Q3.1 through 2023.Q4.6. The vulnerability stems from insufficient input validation and output encoding of the 'redirect' parameter in the Announcements and Alerts modules. Attackers can craft malicious URLs containing executable JavaScript or HTML payloads within this parameter. When a victim clicks such a link, the injected script executes in the context of the victim's browser, potentially stealing session cookies, performing actions on behalf of the user, or redirecting to malicious sites. The CVSS 4.0 base score of 4.8 reflects a medium severity, with network attack vector, low attack complexity, no privileges required, but user interaction necessary. The vulnerability affects confidentiality and integrity primarily, with limited impact on availability. No patches are linked yet, and no known exploits have been reported, but the presence of this vulnerability in widely used enterprise portal software makes it a notable risk. The reflected nature means the attack requires social engineering to lure users into clicking malicious links. The vulnerability's persistence across multiple versions indicates a systemic input validation issue in the affected components.

For European organizations, this vulnerability poses a risk of session hijacking, credential theft, and unauthorized actions within Liferay portals, which are often used for intranet, collaboration, and customer-facing services. Compromise could lead to data leakage, unauthorized access to sensitive information, and reputational damage. Given Liferay's use in government, education, and enterprise sectors across Europe, exploitation could disrupt critical services or expose confidential data. The requirement for user interaction limits automated exploitation but does not eliminate risk, especially in phishing-prone environments. Attackers could leverage this vulnerability to conduct targeted spear-phishing campaigns against employees or partners. The medium severity suggests moderate urgency, but organizations with high-value data or regulatory compliance obligations (e.g., GDPR) should treat this as a significant threat. The lack of known exploits currently provides a window for proactive mitigation before widespread attacks occur.

Organizations should immediately review and update Liferay Portal and DXP installations to the latest versions once patches become available. In the interim, implement strict input validation and output encoding on the 'redirect' parameter at the application level to neutralize malicious scripts. Deploy Web Application Firewalls (WAFs) with custom rules to detect and block suspicious payloads targeting the vulnerable parameters. Conduct user awareness training to recognize and avoid phishing attempts involving suspicious URLs. Monitor web server logs for unusual requests containing script tags or encoded payloads in the 'redirect' parameter. Disable or restrict the use of the vulnerable Announcements and Alerts components if feasible until patched. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in browsers. Regularly audit and update security controls surrounding Liferay deployments, including authentication and session management mechanisms, to reduce the impact of potential XSS exploitation.