CVE-2025-12393 is a stored cross-site scripting vulnerability identified in the Free Quotation plugin for WordPress, developed by kris_iv. This vulnerability exists in all versions up to and including 3.1.6 and arises due to improper neutralization of input during web page generation, specifically insufficient input sanitization and output escaping in the plugin's admin settings interface. The flaw allows an attacker with administrator-level privileges or higher to inject arbitrary JavaScript code into pages managed by the plugin. This malicious script is stored persistently and executes whenever any user accesses the infected page, potentially compromising user sessions or enabling further attacks such as privilege escalation or data theft. The vulnerability is limited to multi-site WordPress installations where the unfiltered_html capability is disabled, which restricts the ability to post unfiltered HTML content. The CVSS v3.1 base score is 4.4 (medium severity), reflecting that exploitation requires network access, high attack complexity, and high privileges, but no user interaction is needed. The scope is changed (S:C), indicating that the vulnerability affects resources beyond the initially vulnerable component. No patches or known exploits are currently available, emphasizing the need for proactive mitigation. The vulnerability is cataloged under CWE-79, which covers cross-site scripting issues caused by improper input validation and output encoding.

For European organizations, this vulnerability poses a moderate risk primarily to those operating WordPress multi-site environments with the Free Quotation plugin installed. Successful exploitation could lead to unauthorized script execution in the context of users visiting affected pages, potentially resulting in session hijacking, credential theft, or unauthorized actions performed on behalf of users. Although exploitation requires administrator-level access, insider threats or compromised admin accounts could leverage this vulnerability to escalate attacks. The impact on confidentiality and integrity is low to moderate, while availability is not affected. Given the widespread use of WordPress in Europe, especially in sectors like media, education, and small to medium enterprises, this vulnerability could facilitate targeted attacks against these organizations. The multi-site limitation narrows the affected population but does not eliminate risk, as multi-site setups are common in large organizations and agencies managing multiple domains. The absence of known exploits reduces immediate risk but does not preclude future exploitation attempts.

To mitigate CVE-2025-12393, European organizations should: 1) Immediately audit WordPress installations to identify multi-site environments using the Free Quotation plugin up to version 3.1.6. 2) Restrict administrator-level access strictly to trusted personnel and enforce strong authentication mechanisms such as multi-factor authentication (MFA). 3) Disable or limit the use of the Free Quotation plugin if it is not essential, or upgrade to a patched version once available. 4) Implement Web Application Firewalls (WAF) with custom rules to detect and block suspicious script injection attempts in admin settings. 5) Monitor logs and admin activity for unusual changes or script insertions. 6) Employ Content Security Policy (CSP) headers to reduce the impact of potential XSS payloads. 7) Educate administrators on secure plugin management and the risks of stored XSS vulnerabilities. 8) Regularly back up WordPress sites to enable rapid recovery if compromise occurs. These steps go beyond generic advice by focusing on the specific conditions of this vulnerability, such as multi-site configurations and admin-level access.