CVE-2025-13738 identifies a stored Cross-Site Scripting (XSS) vulnerability in the Easy Table of Contents plugin developed by magazine3 for WordPress. This vulnerability arises from improper neutralization of input during web page generation (CWE-79), specifically due to insufficient sanitization and escaping of user-supplied attributes within the 'ez-toc' shortcode. The flaw affects all versions up to and including 2.0.78. An attacker with authenticated access at the contributor level or above can inject arbitrary JavaScript code into pages by manipulating shortcode attributes. Because the malicious script is stored persistently, it executes every time a user accesses the compromised page, potentially leading to session hijacking, privilege escalation, or defacement. The vulnerability has a CVSS 3.1 base score of 6.4, reflecting medium severity, with an attack vector of network (remote), low attack complexity, requiring low privileges, no user interaction, and a scope change indicating impact beyond the vulnerable component. No patches or official fixes are currently available, and no known exploits have been reported in the wild. The vulnerability highlights the risk of insufficient input validation in WordPress plugins, especially those that allow user-generated content or shortcode customization.

For European organizations, this vulnerability poses a moderate risk primarily to websites running WordPress with the Easy Table of Contents plugin installed. Attackers with contributor-level access—often content creators or editors—can exploit this flaw to inject malicious scripts that execute in the browsers of site visitors, including administrators and other users. This can lead to theft of authentication cookies, unauthorized actions on behalf of users, defacement, or distribution of malware. Organizations relying on WordPress for publishing and collaboration may face reputational damage, data leakage, and potential regulatory compliance issues under GDPR if user data is compromised. The impact is heightened in environments with multiple contributors or where contributor accounts are not tightly controlled. Since the vulnerability does not require user interaction, the risk of automated exploitation is higher once an attacker gains contributor access. However, the absence of known exploits in the wild suggests the threat is currently moderate but could escalate if weaponized.

1. Immediately audit and restrict contributor-level access to trusted users only, minimizing the number of accounts with permissions to use the 'ez-toc' shortcode. 2. Monitor and review existing content for suspicious or unexpected shortcode attributes that could indicate prior exploitation. 3. Implement Web Application Firewall (WAF) rules to detect and block malicious script patterns in shortcode parameters. 4. Disable or remove the Easy Table of Contents plugin if it is not essential to reduce the attack surface. 5. Follow closely for official patches or updates from magazine3 and apply them promptly once released. 6. Educate content contributors about secure content practices and the risks of injecting untrusted code. 7. Employ Content Security Policy (CSP) headers to limit the impact of potential XSS by restricting script sources. 8. Regularly back up website content and configurations to enable quick restoration if compromise occurs. 9. Use security plugins that scan for malicious code injections in WordPress content. These targeted steps go beyond generic advice by focusing on access control, monitoring, and layered defenses specific to this plugin’s vulnerability.