CVE-2025-5807 Overview
CVE-2025-5807 is a stored Cross-Site Scripting (XSS) vulnerability affecting the Gwolle Guestbook plugin for WordPress. The flaw exists in all versions up to and including 4.9.2. The vulnerability stems from insufficient input sanitization and output escaping of the gwolle_gb_content parameter. Unauthenticated attackers can inject arbitrary web scripts that execute when users visit affected pages. The issue is classified under CWE-79 for improper neutralization of input during web page generation.
Critical Impact
Unauthenticated attackers can inject persistent JavaScript payloads that execute in the browsers of site visitors, enabling session theft, credential harvesting, and administrative account compromise.
Affected Products
- Gwolle Guestbook plugin for WordPress, versions up to and including 4.9.2
- WordPress installations with the vulnerable plugin activated
- Any site exposing the guestbook submission interface to unauthenticated users
Discovery Timeline
- 2025-07-10 - CVE-2025-5807 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-5807
Vulnerability Analysis
The vulnerability resides in the Gwolle Guestbook plugin's handling of user-supplied content submitted through the gwolle_gb_content parameter. The plugin fails to properly sanitize input before storing it and fails to escape the stored content when rendering it back to visitors. Attackers can submit guestbook entries containing malicious HTML or JavaScript payloads. Once stored, these payloads execute in the browsers of any users who load the affected guestbook page. The attack requires user interaction, since the victim must navigate to a page containing the injected content.
Root Cause
The root cause is a combination of two coding failures within the plugin. First, the plugin does not sanitize the gwolle_gb_content input on submission using functions such as wp_kses or equivalent allow-list filtering. Second, the plugin echoes stored content into HTML output without applying context-appropriate escaping via esc_html, esc_attr, or wp_kses_post. This dual gap allows unsanitized script tags and event handlers to survive persistence and reach the DOM.
Attack Vector
Exploitation is performed remotely over the network without authentication. An attacker submits a crafted guestbook entry containing JavaScript in the gwolle_gb_content field. The malicious payload is stored in the WordPress database. When any visitor, including administrators, loads the guestbook page, the browser executes the injected script under the site's origin. This enables session cookie theft, forced administrative actions via authenticated Cross-Site Request Forgery, drive-by redirects, and phishing overlays targeting site users.
No verified public exploit code is available at the time of publication. See the Wordfence Vulnerability Report for additional technical details.
Detection Methods for CVE-2025-5807
Indicators of Compromise
- Guestbook entries containing <script> tags, javascript: URIs, or event handler attributes such as onerror, onload, or onclick
- Database rows in the Gwolle Guestbook tables containing encoded HTML entities or unusual Unicode escapes designed to bypass filters
- Unexpected outbound requests from visitor browsers to attacker-controlled domains originating from guestbook pages
- Administrator sessions performing unexpected privileged actions shortly after viewing guestbook content
Detection Strategies
- Review the wp_gwolle_gb_entries table for entries with HTML tags, script content, or suspicious attribute patterns in the content column
- Monitor web server logs for POST requests to guestbook submission endpoints containing URL-encoded script payloads
- Deploy a Content Security Policy in report-only mode to identify inline script violations on pages hosting the plugin
Monitoring Recommendations
- Enable WordPress audit logging to capture guestbook submission activity, including source IP and submitted content
- Alert on any script or iframe tags appearing in guestbook database entries via scheduled database queries
- Monitor browser telemetry and endpoint logs for anomalous JavaScript execution or credential prompts originating from the WordPress site
How to Mitigate CVE-2025-5807
Immediate Actions Required
- Update the Gwolle Guestbook plugin to the patched version released after 4.9.2 as referenced in the WordPress Change Log Entry
- Audit existing guestbook entries and purge any records containing script tags, event handlers, or obfuscated JavaScript
- Force password rotation for administrative accounts if evidence of exploitation exists
Patch Information
The plugin maintainers addressed the vulnerability in the changeset published at plugins.trac.wordpress.org changeset 3316455. The fix introduces proper sanitization of the gwolle_gb_content parameter and output escaping when rendering stored entries. Administrators should apply the update through the WordPress plugin dashboard or via wp-cli immediately.
Workarounds
- Deactivate the Gwolle Guestbook plugin until the patched version can be installed
- Restrict guestbook submission endpoints via web application firewall rules that block requests containing <script> or javascript: patterns in the gwolle_gb_content field
- Implement a strict Content Security Policy that disallows inline scripts to reduce the impact of stored XSS payloads
# Update the plugin via wp-cli
wp plugin update gwolle-gb
# Verify the installed version is above 4.9.2
wp plugin get gwolle-gb --field=version
# Temporary mitigation: deactivate until patched
wp plugin deactivate gwolle-gb
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
