CVE-2025-6681 is a stored Cross-Site Scripting (XSS) vulnerability identified in the delower186 Fan Page plugin for WordPress, affecting all versions up to and including 1.0.1. The root cause is insufficient input sanitization and output escaping of the 'width' parameter, which is used during web page generation. Authenticated users with Contributor-level permissions or higher can exploit this flaw by injecting arbitrary JavaScript code into pages. Because the injection is stored, the malicious script executes whenever any user accesses the infected page, potentially compromising user sessions, stealing cookies, or performing unauthorized actions on behalf of users. The vulnerability does not require user interaction to trigger once the malicious content is stored. The CVSS 3.1 base score is 6.4, reflecting a medium severity with network attack vector, low attack complexity, and privileges required at the contributor level. The scope is changed (S:C) because the vulnerability affects resources beyond the attacker’s privileges, impacting confidentiality and integrity but not availability. No patches or official fixes are currently linked, and no known exploits have been reported in the wild. This vulnerability highlights the risks of improper input validation in WordPress plugins, especially those that allow content contributions from authenticated users.

The primary impact of this vulnerability is on the confidentiality and integrity of user data and site content. Attackers with Contributor-level access can inject malicious scripts that execute in the context of other users’ browsers, potentially leading to session hijacking, credential theft, or unauthorized actions such as content modification or privilege escalation through chained attacks. While availability is not directly affected, the trustworthiness of the affected websites can be severely damaged, leading to reputational harm and loss of user confidence. Organizations relying on the delower186 Fan Page plugin face risks of data leakage and unauthorized access, especially if their user base includes privileged contributors. The vulnerability could also be leveraged in targeted attacks against high-value WordPress sites, including corporate blogs, community portals, or membership sites. Since exploitation requires authenticated access, the threat is more contained but still significant in environments with multiple contributors or less stringent access controls.

To mitigate this vulnerability, organizations should first check for updates or patches from the plugin vendor and apply them promptly once available. In the absence of official patches, administrators should consider disabling or uninstalling the delower186 Fan Page plugin if it is not essential. For sites that must continue using the plugin, implement strict input validation and output encoding on the 'width' parameter at the application level, possibly via custom code or security plugins that sanitize inputs. Restrict Contributor-level permissions to trusted users only and monitor user activities for suspicious behavior. Employ Web Application Firewalls (WAFs) with rules designed to detect and block XSS payloads targeting the affected parameter. Regularly audit and review content submitted by contributors to detect injected scripts. Additionally, enable Content Security Policy (CSP) headers to limit the impact of any injected scripts by restricting the sources from which scripts can be loaded. Finally, educate contributors about safe content practices and the risks of XSS.