CVE-2025-58850 is a stored Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the Showpass WordPress Extension developed by marcshowpass. This vulnerability arises due to improper neutralization of input during web page generation, allowing malicious actors to inject and persist executable scripts within the application. Specifically, the flaw exists in versions up to 4.0.3 of the Showpass WordPress Extension. When exploited, an attacker can inject malicious JavaScript code that is stored on the server and subsequently executed in the browsers of users who visit the affected pages. The CVSS v3.1 base score is 6.5, indicating a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L) reveals that the attack can be performed remotely over the network with low attack complexity, requires privileges (PR:L) and user interaction (UI:R), and impacts confidentiality, integrity, and availability to a limited extent. The vulnerability’s scope is changed (S:C), meaning it affects components beyond the vulnerable module. Stored XSS vulnerabilities can lead to session hijacking, defacement, phishing, or distribution of malware, posing significant risks to website users and administrators. No known exploits are currently reported in the wild, and no patches have been linked yet, indicating that mitigation may require vendor updates or manual intervention. Given that this is a WordPress extension, the vulnerability is relevant to websites using Showpass for event ticketing or access management, which may process user inputs insufficiently sanitized before rendering.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on the Showpass WordPress Extension for event management, ticketing, or access control on their websites. Exploitation could allow attackers to execute malicious scripts in the context of the affected site, potentially leading to theft of user credentials, session tokens, or personal data, violating GDPR requirements. This could result in reputational damage, regulatory fines, and loss of customer trust. Additionally, attackers might deface websites or redirect users to malicious sites, impacting business continuity and user experience. Since the vulnerability requires some level of privilege and user interaction, internal users or authenticated customers could be targeted to escalate attacks. The scope change indicates that the vulnerability could affect other components or user roles beyond the immediate plugin, increasing the risk of lateral movement within the web application environment. Organizations with high web traffic or those hosting sensitive user data are particularly at risk. The absence of known exploits in the wild provides a window for proactive mitigation, but the lack of available patches necessitates immediate attention to reduce exposure.

European organizations should take the following specific actions to mitigate this vulnerability: 1) Immediately audit all WordPress sites using the Showpass extension to identify affected versions (up to 4.0.3). 2) Temporarily disable or restrict access to the Showpass plugin if feasible until a vendor patch is released. 3) Implement Web Application Firewall (WAF) rules specifically targeting common XSS payloads and patterns associated with Showpass plugin inputs to block malicious requests. 4) Conduct thorough input validation and output encoding on all user-supplied data related to the plugin, applying context-aware escaping to prevent script injection. 5) Educate authenticated users about the risks of interacting with suspicious content and encourage cautious behavior to reduce user interaction exploitation. 6) Monitor web server and application logs for unusual activity or attempts to inject scripts. 7) Engage with the vendor (marcshowpass) for timely updates and patches, and subscribe to security advisories. 8) Prepare incident response plans to quickly address any exploitation attempts. 9) Consider deploying Content Security Policy (CSP) headers to restrict script execution sources, mitigating the impact of potential XSS attacks. These steps go beyond generic advice by focusing on immediate containment, proactive detection, and user awareness tailored to the specific plugin and vulnerability context.