CVE-2025-58974 is a Stored Cross-Site Scripting (XSS) vulnerability identified in the WPComplete plugin developed by StellarWP. This vulnerability arises due to improper neutralization of user-supplied input during web page generation, classified under CWE-79. The flaw allows an attacker with at least low privileges (PR:L) and requiring user interaction (UI:R) to inject malicious scripts that are persistently stored and later executed in the context of other users visiting the affected pages. The vulnerability affects all versions of WPComplete up to and including 2.9.5.2. The CVSS 3.1 base score is 6.5, indicating a medium severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), and a scope change (S:C) meaning the vulnerability can affect resources beyond the initially vulnerable component. The impact includes limited confidentiality, integrity, and availability losses (C:L/I:L/A:L). No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability requires an authenticated user with some privileges to inject the payload, and a victim user to interact with the malicious content for exploitation to succeed. Stored XSS can lead to session hijacking, defacement, or distribution of malware, posing significant risks especially in environments where WPComplete is used to manage learning or content completion workflows on WordPress sites.

For European organizations, particularly those using WordPress with the WPComplete plugin to manage e-learning or content completion, this vulnerability could lead to unauthorized access to user sessions, theft of sensitive information, or manipulation of site content. Given the persistent nature of stored XSS, attackers could target administrators or users with elevated privileges, potentially escalating the impact. This could disrupt business operations, damage reputation, and lead to non-compliance with GDPR if personal data is compromised. The medium severity suggests a moderate risk, but the scope change and ability to affect multiple users elevate the concern. Organizations in sectors such as education, training, and corporate learning platforms are especially at risk, as they often rely on WPComplete for tracking progress and engagement. The absence of known exploits currently provides a window for proactive mitigation before widespread exploitation occurs.

European organizations should immediately audit their WordPress installations to identify the use of the WPComplete plugin and verify the version in use. Until an official patch is released, administrators should consider disabling or uninstalling the plugin if feasible. Implementing Web Application Firewalls (WAFs) with rules to detect and block common XSS payloads can provide interim protection. Additionally, enforcing strict Content Security Policies (CSP) can mitigate the impact of injected scripts by restricting script execution sources. User input validation and sanitization should be reviewed and enhanced wherever possible, especially for inputs that WPComplete processes. Monitoring logs for unusual activity or injection attempts is recommended. Organizations should also educate users about the risks of interacting with suspicious content and ensure that user privileges are minimized to the least necessary level to reduce the attack surface. Once a patch is available, prompt application is critical. Regular backups and incident response plans should be updated to handle potential exploitation scenarios.