CVE-2025-14340 is a cross-site scripting (XSS) vulnerability identified in the REST Management Interface of Payara Server, a widely used Java EE application server platform. The vulnerability arises from improper neutralization of input during web page generation (CWE-79), allowing malicious scripts embedded in crafted URL payloads to be executed in the context of an administrator's browser session. Specifically, the flaw enables an attacker to mislead an administrator into changing the admin password by injecting malicious content into the REST interface responses. The affected versions include multiple releases before 4.1.2.191.54, 5.83.0, 6.34.0, and 7.2026.1, indicating a broad range of impacted deployments. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:H but with user interaction UI:A), and high impact on confidentiality, integrity, and availability (C:H, I:H, A:H). The vulnerability requires user interaction, meaning the administrator must be tricked into clicking or visiting a malicious URL. No known public exploits have been reported yet, but the potential for administrative credential compromise and subsequent full control over the server makes this a critical concern. The vulnerability affects the REST Management Interface, which is often exposed internally or externally for administrative tasks, increasing the risk if access controls are insufficient. The root cause is the failure to properly sanitize or encode user-supplied input before rendering it in the web interface, allowing script injection and execution.

For European organizations, this vulnerability poses a serious risk to the security of Payara Server deployments, especially those exposing the REST Management Interface to internal networks or the internet. Successful exploitation can lead to unauthorized administrative password changes, resulting in full compromise of the server and potentially the applications it hosts. This can cause data breaches, service disruption, and unauthorized access to sensitive business logic or customer data. Organizations in sectors such as finance, government, healthcare, and critical infrastructure that rely on Payara Server for enterprise applications are particularly vulnerable. The impact extends beyond confidentiality to integrity and availability, as attackers gaining admin access can manipulate configurations, deploy malicious code, or disrupt services. The requirement for user interaction means phishing or social engineering attacks targeting administrators are likely attack vectors. Given the high CVSS score and the administrative nature of the vulnerability, the potential operational and reputational damage is significant.

European organizations should immediately assess their Payara Server versions and upgrade to the patched versions 4.1.2.191.54, 5.83.0, 6.34.0, or 7.2026.1 or later. If immediate patching is not feasible, restrict access to the REST Management Interface using network segmentation, firewall rules, and VPNs to limit exposure only to trusted administrators. Implement multi-factor authentication (MFA) for administrative access to reduce the risk of credential misuse. Educate administrators about phishing and social engineering risks, emphasizing caution when clicking on URLs related to management interfaces. Enable logging and monitoring of REST interface access to detect suspicious activities. Consider deploying web application firewalls (WAFs) with custom rules to detect and block XSS payloads targeting the management interface. Regularly review and audit administrative accounts and password policies to ensure strong, unique credentials. Finally, conduct penetration testing and vulnerability scanning focused on management interfaces to identify and remediate similar issues proactively.