CVE-2026-0913 is a stored cross-site scripting vulnerability classified under CWE-79, found in the WordPress plugin 'User Submitted Posts – Enable Users to Submit Posts from the Front End' developed by specialk. This plugin allows users to submit posts from the front end of a WordPress site. The vulnerability arises from insufficient sanitization and escaping of user-supplied attributes in the 'usp_access' shortcode. Authenticated users with Contributor-level permissions or higher can exploit this flaw by injecting arbitrary JavaScript code into posts. Because the malicious script is stored, it executes whenever any user views the compromised page, potentially leading to session hijacking, privilege escalation, or other malicious activities affecting confidentiality and integrity. The vulnerability affects all plugin versions up to and including 20260110. The CVSS 3.1 score is 6.4, reflecting a medium severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with no availability impact. No public exploits have been reported yet. The vulnerability's scope is limited to WordPress sites using this plugin and having users with Contributor or higher roles able to submit content. The issue highlights the importance of proper input validation and output encoding in web applications, especially those allowing user-generated content. Since WordPress is widely used across Europe, this vulnerability poses a risk to many organizations relying on this plugin for front-end content submission.

For European organizations, the impact of CVE-2026-0913 can be significant, especially for those operating WordPress sites with the affected plugin installed and Contributor-level users enabled. Exploitation can lead to unauthorized script execution in the context of site visitors or administrators, potentially resulting in session hijacking, theft of sensitive information, defacement, or further compromise of the website. This can damage organizational reputation, lead to data breaches involving personal data protected under GDPR, and cause operational disruptions. Since the vulnerability requires authenticated access at Contributor level, organizations with lax user role management or large user bases with such privileges are at higher risk. The stored nature of the XSS means the malicious payload persists and can affect multiple users over time. Given the widespread use of WordPress in Europe for corporate, governmental, and media websites, the threat could affect sectors including public administration, media, education, and e-commerce. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits rapidly once the vulnerability is public.

1. Immediately restrict Contributor-level permissions to trusted users only and review user roles to minimize the number of users who can submit posts from the front end. 2. Monitor and audit all user-submitted content for suspicious scripts or code injections. 3. Implement additional server-side input validation and output encoding for all user-supplied data, especially for shortcodes like 'usp_access'. 4. Apply security plugins or Web Application Firewalls (WAFs) that can detect and block XSS payloads targeting WordPress sites. 5. Stay alert for official patches or updates from the plugin developer and apply them promptly once released. 6. Consider temporarily disabling the affected plugin if feasible until a patch is available. 7. Educate site administrators and users about the risks of XSS and safe content submission practices. 8. Employ Content Security Policy (CSP) headers to limit the impact of any injected scripts. 9. Regularly back up website data to enable quick recovery in case of compromise. 10. Conduct penetration testing focused on user input vectors to identify any residual vulnerabilities.