CVE-2025-58806: Bugsnag WordPress Plugin CSRF Vulnerability

CVE-2025-58806 Overview

A Cross-Site Request Forgery (CSRF) vulnerability has been identified in the WordPress Error Monitoring by Bugsnag plugin, developed by Tom Longridge. This vulnerability allows attackers to perform Stored Cross-Site Scripting (XSS) attacks by exploiting the lack of proper CSRF token validation in plugin functionality. When successfully exploited, an attacker can trick an authenticated administrator into submitting malicious requests, resulting in persistent XSS payloads being stored within the WordPress installation.

Critical Impact

This chained CSRF to Stored XSS vulnerability enables attackers to execute arbitrary JavaScript in the context of authenticated administrator sessions, potentially leading to full site compromise, credential theft, and malware distribution to site visitors.

Affected Products

• WordPress Error Monitoring by Bugsnag plugin version 1.6.3 and earlier
• All WordPress installations utilizing the affected Bugsnag plugin versions
• WordPress sites where administrators access the Bugsnag plugin settings

Discovery Timeline

• 2025-09-05 - CVE-2025-58806 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-58806

Vulnerability Analysis

This vulnerability combines two distinct attack vectors: Cross-Site Request Forgery (CSRF) and Stored Cross-Site Scripting (XSS). The WordPress Error Monitoring by Bugsnag plugin fails to implement proper nonce verification on sensitive administrative actions, allowing external websites to submit forged requests on behalf of authenticated administrators. This CSRF weakness serves as the entry point for injecting malicious scripts that are then stored persistently within the plugin's settings or data storage.

The attack chain requires an authenticated administrator to visit a malicious webpage while logged into the vulnerable WordPress installation. The malicious page contains a hidden form or JavaScript that automatically submits a request to the WordPress admin interface, bypassing the lack of CSRF protections to inject XSS payloads into plugin settings fields.

Root Cause

The root cause of this vulnerability lies in CWE-352 (Cross-Site Request Forgery). The Bugsnag plugin does not properly validate WordPress nonces on form submissions and AJAX requests within its administrative interface. Additionally, inadequate input sanitization and output encoding allow attacker-controlled data to be stored and later rendered without proper escaping, enabling the Stored XSS component of this attack.

Attack Vector

The attack requires social engineering to lure an authenticated WordPress administrator to a malicious website. The attacker's site contains crafted HTML or JavaScript that automatically submits a forged request to the vulnerable plugin endpoint. Since the plugin lacks CSRF token validation, the request is processed as legitimate. The malicious payload, typically JavaScript code, is then stored within the plugin's configuration or database entries. When any administrator subsequently views the affected settings page, the stored XSS payload executes in their browser context.

The attack does not require any user interaction beyond visiting the malicious page, as modern techniques allow automatic form submission without user awareness. Once the XSS payload is stored, it persists and executes for all administrators accessing the affected functionality.

Detection Methods for CVE-2025-58806

Indicators of Compromise

• Unexpected JavaScript code or HTML tags present in Bugsnag plugin settings or configuration fields
• Suspicious administrative activity logs showing settings changes without corresponding legitimate admin sessions
• Browser console errors indicating blocked or executed scripts from unexpected origins
• Unusual network requests originating from WordPress admin pages to external domains

Detection Strategies

• Review WordPress activity logs for unauthorized modifications to Bugsnag plugin settings
• Implement Content Security Policy (CSP) headers to detect and block unauthorized script execution
• Monitor for suspicious iframe or form elements on external sites targeting your WordPress admin URLs
• Conduct regular audits of plugin settings fields for injected malicious content

Monitoring Recommendations

• Enable WordPress security plugins that log administrative actions and detect anomalous behavior
• Configure web application firewall (WAF) rules to block requests lacking proper referer headers to sensitive endpoints
• Implement real-time alerting for changes to plugin configuration values
• Monitor outbound network connections from WordPress admin sessions for suspicious destinations

How to Mitigate CVE-2025-58806

Immediate Actions Required

• Deactivate and remove the WordPress Error Monitoring by Bugsnag plugin version 1.6.3 or earlier until a patched version is available
• Audit Bugsnag plugin settings and database entries for any injected malicious scripts or HTML
• Review WordPress admin activity logs for any unauthorized changes or suspicious access patterns
• Clear browser caches for administrators who have accessed the plugin settings page

Patch Information

At the time of publication, users should check the Patchstack CSRF Vulnerability Report for the latest remediation guidance and patch availability. Monitor the official WordPress plugin repository for updated versions of the Bugsnag plugin that address this vulnerability.

Workarounds

• Implement a web application firewall (WAF) with CSRF protection rules to filter suspicious requests
• Add custom nonce verification to the plugin's vulnerable endpoints if source code modification is feasible
• Restrict administrative access to trusted IP addresses to limit attack surface
• Educate administrators to avoid clicking suspicious links or visiting untrusted websites while logged into WordPress

# Example: Add IP restriction to wp-admin in .htaccess
<IfModule mod_rewrite.c>
    RewriteEngine on
    RewriteCond %{REQUEST_URI} ^/wp-admin
    RewriteCond %{REMOTE_ADDR} !^192\.168\.1\.100$
    RewriteRule ^(.*)$ - [R=403,L]
</IfModule>