CVE-2025-14548 is a stored Cross-Site Scripting (XSS) vulnerability identified in the kieranoshea Calendar plugin for WordPress, affecting all versions up to and including 1.3.16. The root cause is improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of the 'event_desc' parameter. This flaw allows authenticated users with Contributor-level permissions or higher to inject arbitrary JavaScript code into calendar event descriptions. When other users, including administrators, view the affected calendar pages, the malicious scripts execute in their browsers, potentially leading to session hijacking, privilege escalation, or unauthorized actions within the WordPress environment. The exploitation requires that administrators enable lower-privilege users to manage calendar events via plugin settings, which is not the default configuration, thus limiting the attack surface. The vulnerability has a CVSS v3.1 base score of 6.4, reflecting medium severity, with an attack vector of network (remote), low attack complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with no effect on availability. No public exploits have been reported yet. The vulnerability was published on December 23, 2025, and assigned by Wordfence. Since the plugin is widely used in WordPress sites for event management, this vulnerability poses a significant risk if exploited, especially in environments with multiple contributors and relaxed permission settings.

For European organizations, this vulnerability could lead to unauthorized script execution within their WordPress sites, compromising user sessions, stealing sensitive data, or performing unauthorized actions under the guise of legitimate users. The impact is primarily on confidentiality and integrity, as attackers could hijack administrator sessions or manipulate site content. Although availability is not directly affected, the reputational damage and potential data breaches could have regulatory and compliance consequences under GDPR. Organizations with collaborative websites that allow multiple contributors to manage content are at higher risk, especially if they have enabled lower-privilege users to manage calendar events. The risk is amplified in sectors such as government, education, and media, where WordPress is commonly used and where sensitive information may be exposed. The absence of known exploits in the wild provides a window for proactive mitigation, but the medium severity score indicates that timely patching or configuration changes are necessary to prevent exploitation.

1. Immediately review and restrict permissions in the WordPress environment to ensure that only trusted users have Contributor-level or higher access, and avoid enabling lower-privilege users to manage calendar events unless absolutely necessary. 2. Apply strict input validation and output escaping for all user-supplied data, particularly the 'event_desc' parameter, either by updating the plugin when a patch is released or by implementing custom sanitization filters via WordPress hooks. 3. Monitor WordPress user activity logs for unusual event creation or modification patterns that could indicate exploitation attempts. 4. Employ a Web Application Firewall (WAF) with rules designed to detect and block XSS payloads targeting the calendar plugin. 5. Educate administrators and content managers about the risks of enabling event management for lower-privilege users and encourage the principle of least privilege. 6. Regularly update all WordPress plugins and core installations to the latest versions once the vendor releases a patch addressing this vulnerability. 7. Consider isolating or disabling the calendar plugin if it is not essential to reduce the attack surface until a fix is available.