CVE-2025-6588 Overview
CVE-2025-6588 is a Reflected Cross-Site Scripting (XSS) vulnerability affecting the FunnelCockpit plugin for WordPress. The flaw exists in all versions up to and including 1.4.3 and stems from insufficient input sanitization and output escaping of the error parameter. Unauthenticated attackers can craft malicious links that, when clicked by an administrative user, execute arbitrary JavaScript in the browser context. The weakness is classified under CWE-79. Successful exploitation can lead to session token theft, administrative account takeover, or malicious redirection.
Critical Impact
Attackers who trick a WordPress administrator into clicking a crafted URL can execute arbitrary scripts in the admin session, enabling account compromise and site takeover.
Affected Products
- FunnelCockpit plugin for WordPress, versions up to and including 1.4.3
- WordPress installations with the vulnerable plugin activated
- Administrative user sessions targeted through crafted links
Discovery Timeline
- 2025-07-24 - CVE-2025-6588 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-6588
Vulnerability Analysis
The FunnelCockpit plugin renders the value of the error query parameter back into a page served to administrators without applying proper sanitization or output escaping. Because the reflected value is placed into HTML context, an attacker can inject arbitrary markup and JavaScript through the URL. The vulnerability requires no authentication for the attacker but requires user interaction from a privileged victim, typically a WordPress administrator. The attack scope is changed because scripts execute in the trusted admin origin, giving attackers access to any data or actions available to the victim. Exploitation typically occurs through phishing emails, social media messages, or malicious sites that link to the crafted URL.
Root Cause
The root cause is missing input validation and missing output escaping on the error parameter processed by the plugin's admin handler. Referenced code in the WordPress plugin repository at admin/class-funnelcockpit-admin.php line 433 shows the reflection point. Vendor changeset 3337752 addresses the flaw by introducing proper escaping before the value is emitted into HTML.
Attack Vector
The attack vector is network-based and relies on user interaction. An attacker constructs a URL targeting the vulnerable admin endpoint with a payload placed in the error parameter, for example a <script> tag or an event handler carrying JavaScript. The attacker then delivers this URL to an authenticated administrator through phishing or a malicious referrer. When the administrator opens the link while logged into WordPress, the injected script executes with the administrator's privileges, allowing session cookie exfiltration, creation of new admin accounts, plugin modification, or arbitrary API calls against the site.
No verified public proof-of-concept code is available. See the Wordfence Vulnerability Report and the WordPress Plugin Code Review for technical details.
Detection Methods for CVE-2025-6588
Indicators of Compromise
- Web server access logs containing requests to FunnelCockpit admin endpoints with an error parameter carrying HTML tags, <script>, javascript:, or event handlers such as onerror= and onload=.
- URL-encoded payloads targeting the error parameter, including sequences like %3Cscript%3E or %22%3E%3Csvg.
- Unexpected creation of new WordPress administrator accounts or plugin/theme modifications following clicks on external links by admins.
- Outbound connections from admin browsers to unfamiliar domains immediately after loading a WordPress admin page.
Detection Strategies
- Inspect HTTP query strings for the error parameter and alert on values containing HTML metacharacters or script tokens.
- Correlate admin session activity with recent referrers from external or untrusted domains.
- Monitor WordPress audit logs for privilege changes, user creation, or option updates immediately following admin navigation events.
Monitoring Recommendations
- Enable a Web Application Firewall (WAF) with rules that block reflected XSS payloads on WordPress admin routes.
- Forward WordPress access, error, and audit logs to a centralized analytics platform for correlation and retention.
- Track plugin inventory and version data across sites to identify installations still running FunnelCockpit 1.4.3 or earlier.
How to Mitigate CVE-2025-6588
Immediate Actions Required
- Update the FunnelCockpit plugin to the version released in changeset 3337752 or later, which introduces proper escaping of the error parameter.
- Deactivate and remove the FunnelCockpit plugin on any site where updating is not immediately possible.
- Rotate WordPress administrator passwords and invalidate active sessions if suspicious error parameter activity is found in logs.
- Educate administrators to avoid clicking WordPress admin URLs received from untrusted sources.
Patch Information
The vendor addressed the vulnerability in WordPress Changeset #3337752. Site owners should upgrade FunnelCockpit to the fixed version published after this changeset. The patched build sanitizes and escapes the error parameter before it is reflected into the response.
Workarounds
- Deploy a WAF rule that strips or blocks HTML metacharacters in the error query parameter on WordPress admin paths.
- Restrict access to /wp-admin by IP allowlist so that only trusted network ranges can reach vulnerable endpoints.
- Enforce a strict Content-Security-Policy header on the WordPress admin interface to limit inline script execution.
# Example WAF rule (ModSecurity) to block script payloads in the 'error' parameter
SecRule ARGS:error "@rx (?i)(<script|javascript:|onerror=|onload=|<svg)" \
"id:1006588,phase:2,deny,status:403,log,\
msg:'Blocked reflected XSS attempt against FunnelCockpit (CVE-2025-6588)'"
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
