CVE-2025-11453 is a stored Cross-Site Scripting vulnerability identified in the 'Header and Footer Scripts' WordPress plugin developed by anand_kumar. This plugin allows users to add custom scripts to the header and footer sections of WordPress pages. The vulnerability exists due to improper neutralization of input during web page generation, specifically insufficient sanitization and escaping of the _inpost_head_script parameter. Authenticated users with Contributor-level access or higher can exploit this flaw to inject arbitrary JavaScript code that is persistently stored and executed whenever any user accesses the affected page. The attack vector is network-based, with low complexity, requiring privileges but no user interaction, and the vulnerability affects all versions up to and including 2.2.2. The impact includes partial loss of confidentiality and integrity, such as theft of session cookies, user impersonation, or manipulation of page content, but does not impact system availability. Although no known exploits are currently in the wild, the vulnerability poses a significant risk to WordPress sites using this plugin, especially those with multiple contributors. The CVSS 3.1 score of 6.4 reflects a medium severity level, emphasizing the need for timely mitigation. The vulnerability is classified under CWE-79, which covers improper input neutralization leading to XSS attacks. Since the plugin is widely used for customizing WordPress sites, the risk extends to many organizations relying on WordPress for their web presence.

For European organizations, this vulnerability can lead to unauthorized script execution on their WordPress sites, potentially compromising user sessions, stealing sensitive information, or defacing web content. Organizations with multiple contributors or editors are particularly vulnerable, as these roles can be leveraged to inject malicious scripts. The impact is heightened for e-commerce, government, and media websites where trust and data confidentiality are critical. Exploitation could facilitate phishing campaigns, spread malware, or enable further lateral attacks within the organization’s network. Although availability is not directly affected, reputational damage and loss of user trust could be significant. The medium severity score indicates a moderate but actionable risk, especially in sectors with strict data protection regulations such as GDPR. Failure to address this vulnerability could lead to compliance issues and financial penalties in the European context.

1. Immediately restrict Contributor-level and higher user privileges to trusted personnel only, minimizing the risk of malicious script injection. 2. Monitor and audit all custom scripts added via the Header and Footer Scripts plugin, looking for suspicious or unauthorized code. 3. Implement Web Application Firewall (WAF) rules to detect and block common XSS payloads targeting this plugin. 4. Encourage users to apply the latest plugin updates as soon as patches become available; in the absence of official patches, consider temporarily disabling the plugin or replacing it with a secure alternative. 5. Employ Content Security Policy (CSP) headers to limit the execution of unauthorized scripts on affected sites. 6. Conduct regular security training for contributors to raise awareness about the risks of injecting unsafe scripts. 7. Use security plugins that scan for malicious code injections and alert administrators promptly. 8. Review and harden WordPress user roles and permissions to follow the principle of least privilege. These steps go beyond generic advice by focusing on operational controls, monitoring, and layered defenses specific to this vulnerability.