CVE-2025-25125: Fyrebox Quizzes CSRF Vulnerability

CVE-2025-25125 Overview

CVE-2025-25125 is a Cross-Site Request Forgery (CSRF) vulnerability in the Fyrebox Quizzes WordPress plugin (fyrebox-shortcode) that can be chained with Stored Cross-Site Scripting (XSS). This vulnerability allows attackers to trick authenticated administrators into performing unintended actions, ultimately leading to the injection of persistent malicious scripts into the WordPress site.

The vulnerability exists because the plugin fails to implement proper CSRF token validation on critical administrative functions, combined with insufficient output sanitization that enables stored XSS payloads to persist in the database and execute in the browsers of subsequent visitors.

Critical Impact

Attackers can chain CSRF with Stored XSS to compromise WordPress administrator sessions, steal credentials, deface websites, or distribute malware to site visitors through persistent malicious scripts.

Affected Products

• Fyrebox Quizzes WordPress Plugin versions up to and including 3.1
• WordPress installations with the fyrebox-shortcode plugin enabled

Discovery Timeline

• 2025-02-07 - CVE-2025-25125 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-25125

Vulnerability Analysis

This vulnerability represents a classic CSRF-to-Stored XSS attack chain commonly found in WordPress plugins. The Fyrebox Quizzes plugin processes administrative form submissions without validating CSRF nonces, allowing attackers to craft malicious requests that execute when an authenticated administrator visits an attacker-controlled page.

The attack chain works in two stages: First, the CSRF vulnerability allows an attacker to submit arbitrary data to plugin endpoints by forging requests that appear to originate from the victim administrator's session. Second, the lack of proper input sanitization and output encoding allows the injected content to be stored in the WordPress database and rendered as executable JavaScript when the affected pages are viewed.

This chained attack is particularly dangerous because the stored XSS payload persists beyond the initial attack, affecting all users who view the compromised content—including other administrators, editors, and public visitors to the WordPress site.

Root Cause

The root cause of this vulnerability is twofold:

1. Missing CSRF Protection (CWE-352): The plugin fails to implement WordPress nonce verification on state-changing administrative operations. WordPress provides built-in functions like wp_nonce_field() and wp_verify_nonce() specifically to prevent CSRF attacks, but the vulnerable endpoints do not utilize these protections.

2. Insufficient Input Sanitization: User-supplied input is not properly sanitized using WordPress functions like sanitize_text_field() or esc_html() before being stored in the database, and output encoding is missing when rendering the stored data, enabling the XSS component of the attack.

Attack Vector

The attack requires social engineering to succeed. An attacker must craft a malicious HTML page containing a hidden form that targets the vulnerable plugin endpoint. When an authenticated WordPress administrator visits this page, their browser automatically submits the form using their active session cookies.

The attack typically involves:

1. Attacker identifies the vulnerable endpoint in the Fyrebox Quizzes plugin that lacks CSRF protection
2. Attacker crafts a malicious page with an auto-submitting form containing XSS payload
3. Attacker tricks a WordPress administrator into visiting the malicious page (via phishing, comment spam, or other social engineering)
4. The administrator's browser submits the forged request with their session credentials
5. The malicious XSS payload is stored in the WordPress database
6. All subsequent visitors to the affected pages execute the malicious JavaScript in their browsers

The vulnerability can be exploited through standard CSRF techniques such as hidden iframes, auto-submitting forms, or image tags that trigger GET requests. Technical details and proof-of-concept information can be found in the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2025-25125

Indicators of Compromise

• Unexpected JavaScript code or <script> tags appearing in quiz content or plugin settings
• Suspicious admin activity logs showing configuration changes without corresponding legitimate user actions
• Reports of browser-based attacks or unexpected redirects from visitors to pages containing Fyrebox quizzes
• Unusual outbound network requests from the WordPress site to external domains

Detection Strategies

• Review WordPress database tables associated with the Fyrebox Quizzes plugin for stored XSS payloads such as <script>, javascript:, or event handlers like onerror
• Monitor web server access logs for suspicious POST requests to Fyrebox plugin endpoints, especially from external referrers
• Implement Content Security Policy (CSP) headers to detect and block unauthorized script execution
• Use WordPress security plugins to scan for known malicious patterns in stored content

Monitoring Recommendations

• Enable WordPress audit logging to track all administrative changes to plugin settings
• Configure web application firewall (WAF) rules to alert on CSRF attack patterns and XSS payloads
• Regularly review the wp_options table and any custom tables created by the Fyrebox plugin for suspicious content
• Monitor for unusual JavaScript errors or network requests in browser developer tools when testing quiz pages

How to Mitigate CVE-2025-25125

Immediate Actions Required

• Update the Fyrebox Quizzes plugin to a patched version when available from the developer
• If no patch is available, consider temporarily deactivating the fyrebox-shortcode plugin until a fix is released
• Review all existing quiz content for signs of injected malicious scripts
• Implement a Web Application Firewall (WAF) with CSRF and XSS protection rules

Patch Information

Organizations should check the official WordPress plugin repository and the Patchstack Vulnerability Advisory for updated versions of the Fyrebox Quizzes plugin that address this vulnerability. Until a patch is confirmed, treat any version up to and including 3.1 as vulnerable.

Workarounds

• Deactivate the Fyrebox Quizzes plugin if it is not essential to site operations
• Implement additional CSRF protection at the server or WAF level by requiring custom headers on POST requests
• Add Content Security Policy headers to prevent execution of unauthorized inline scripts
• Restrict administrative access to trusted IP addresses to reduce the attack surface for CSRF exploitation

Administrators should exercise caution when clicking links in emails or visiting unfamiliar websites while logged into the WordPress dashboard, as this is the primary attack vector for CSRF vulnerabilities.