CVE-2025-6236: Kibokolabs Hostel WordPress Plugin XSS

CVE-2025-6236 Overview

CVE-2025-6236 is a Stored Cross-Site Scripting (XSS) vulnerability in the Kibokolabs Hostel WordPress plugin versions prior to 1.1.5.9. The plugin fails to sanitize and escape several of its settings inputs. High-privilege users such as administrators can inject arbitrary JavaScript that persists in the plugin configuration. The flaw bypasses the unfiltered_html capability restriction, which normally blocks administrators from posting raw HTML in WordPress multisite installations. This makes the issue relevant to hosted WordPress environments where site administrators are not fully trusted [CWE-79].

Critical Impact

Stored XSS execution in administrator context that bypasses the unfiltered_html capability check enforced in WordPress multisite deployments.

Affected Products

• Kibokolabs Hostel WordPress plugin versions before 1.1.5.9
• WordPress single-site installations with the vulnerable plugin active
• WordPress multisite networks where administrators lack unfiltered_html

Discovery Timeline

• 2025-07-10 - CVE-2025-6236 published to NVD
• 2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-6236

Vulnerability Analysis

The Hostel plugin exposes plugin-specific configuration settings in the WordPress administration interface. Values submitted through these settings are stored without proper sanitization and rendered later without output escaping. An authenticated user with administrative privileges can inject JavaScript payloads that execute in the browser of any user who loads the affected setting page or public-facing content.

The vulnerability is scored with a network attack vector and requires user interaction, reflecting that a victim must load a page containing the injected payload. The scope change reflects the ability of the injected script to act beyond the plugin boundary within the browser Document Object Model (DOM). Its EPSS probability sits at 0.212% at the 11th percentile, indicating low observed exploitation likelihood.

Root Cause

The root cause is missing input sanitization and missing output escaping on plugin settings fields. The plugin does not apply WordPress helpers such as sanitize_text_field() on input nor esc_attr() or esc_html() on output. WordPress normally restricts raw HTML entry to users with the unfiltered_html capability, which is disabled for site administrators in multisite. Because the plugin bypasses this control, administrators can store scripts they would otherwise be prohibited from posting.

Attack Vector

An attacker who has obtained or compromised administrator credentials submits a crafted payload through the vulnerable plugin settings form. The payload is stored in the WordPress options table and rendered whenever the settings page or a page referencing the stored value is loaded. This can be used for session hijacking of other administrators, privilege escalation on multisite networks by pivoting to super-admin actions, or persistent implantation of malicious redirects. See the WPScan Vulnerability Report for technical details.

Detection Methods for CVE-2025-6236

Indicators of Compromise

• Unexpected <script>, onerror=, or onload= strings in Hostel plugin option values stored in the WordPress wp_options table.
• Administrator-initiated POST requests to plugin settings endpoints containing HTML or JavaScript payloads.
• Outbound browser requests from admin sessions to unfamiliar domains after loading Hostel plugin settings pages.

Detection Strategies

• Query the WordPress database for Hostel plugin option rows and inspect stored values for HTML or script tokens.
• Review the plugin version in wp-content/plugins/hostel/ and flag installations at versions below 1.1.5.9.
• Enable WordPress audit logging to capture setting changes performed by administrator accounts.

Monitoring Recommendations

• Monitor web server access logs for administrator POST requests to admin.php?page= endpoints associated with the Hostel plugin.
• Alert on Content Security Policy (CSP) violation reports originating from wp-admin pages.
• Track newly created administrator accounts and unexpected changes to super-admin membership on multisite networks.

How to Mitigate CVE-2025-6236

Immediate Actions Required

• Update the Hostel plugin to version 1.1.5.9 or later on every WordPress site where it is installed.
• Audit stored Hostel plugin settings for previously injected HTML or JavaScript content and remove any unauthorized payloads.
• Rotate credentials for administrator and super-admin accounts and enforce multi-factor authentication.

Patch Information

The vendor addressed the issue in Hostel plugin version 1.1.5.9 by adding sanitization and escaping to the affected settings. Refer to the WPScan Vulnerability Report for confirmed fixed version details.

Workarounds

• Restrict access to the Hostel plugin settings pages to a minimal set of trusted administrators until patching is complete.
• Deploy a Web Application Firewall (WAF) rule to inspect and block HTML or script payloads submitted to Hostel plugin settings endpoints.
• Enforce a strict Content Security Policy on the WordPress admin interface to limit inline script execution.

# Update the Hostel plugin using WP-CLI
wp plugin update hostel --version=1.1.5.9
wp plugin list --name=hostel --fields=name,status,version