CVE-2025-13842 is an authorization bypass vulnerability classified under CWE-639 (Authorization Bypass Through User-Controlled Key) affecting the Breadcrumb NavXT plugin for WordPress, specifically versions up to and including 7.5.0. The root cause lies in the Gutenberg block renderer component of the plugin, located in includes/blocks/build/breadcrumb-trail/render.php, which improperly trusts the 'post_id' parameter obtained from the global $_REQUEST array without validating the requester's authorization to access the referenced post. This parameter can be manipulated by unauthenticated attackers to specify arbitrary post IDs, including those of draft or private posts that should not be publicly accessible. As a result, attackers can enumerate these posts and retrieve breadcrumb trail data, which includes post titles and their hierarchical structure within the site. While the vulnerability does not allow modification or deletion of content (integrity) nor disrupt service availability, it leaks sensitive information that could aid further reconnaissance or targeted attacks. The CVSS v3.1 base score is 5.3 (medium severity), reflecting the network attack vector, low complexity, no privileges required, and no user interaction needed. No patches or exploits are currently publicly available, but the vulnerability has been officially published and should be addressed promptly by site administrators. The affected versions are all versions up to 7.5.0, and the issue stems from insufficient access control checks in the plugin's code handling the Gutenberg block rendering.

For European organizations, this vulnerability primarily threatens the confidentiality of unpublished or private content managed via WordPress sites using the Breadcrumb NavXT plugin. Exposure of draft or private post titles and their hierarchical context can lead to information leakage, potentially revealing sensitive business plans, internal communications, or unpublished product details. This could facilitate social engineering, competitive intelligence gathering, or targeted phishing campaigns. Although the vulnerability does not directly compromise system integrity or availability, the unauthorized disclosure of internal content can damage organizational reputation and trust, especially under stringent European data protection regulations such as GDPR. Organizations in sectors with high confidentiality requirements—such as finance, healthcare, government, and critical infrastructure—are particularly at risk. Additionally, the ease of exploitation without authentication increases the likelihood of opportunistic scanning and data harvesting by malicious actors. The impact is thus moderate but significant in environments where content confidentiality is critical.

To mitigate CVE-2025-13842, European organizations should immediately update the Breadcrumb NavXT plugin to a version where this vulnerability is fixed once available. In the absence of an official patch, administrators can implement temporary mitigations such as restricting access to the Gutenberg block rendering endpoint via web application firewalls (WAFs) or server-level access controls to trusted users only. Reviewing and hardening WordPress permissions to ensure that draft and private posts are not accessible to unauthenticated users is also advisable. Additionally, monitoring web server logs for unusual requests containing 'post_id' parameters targeting the vulnerable plugin paths can help detect exploitation attempts. Organizations should also consider disabling or replacing the Breadcrumb NavXT plugin if it is not essential, or applying custom code patches to validate user authorization before rendering breadcrumb trails. Finally, maintaining regular backups and conducting security audits on WordPress plugins can prevent similar issues.