CVE-2025-39511

Executive Summary

CVE-2025-39511 is a Missing Authorization vulnerability in the ValvePress Pinterest Automatic Pin WordPress plugin (slug: wp-pinterest-automatic). This flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized actions within the plugin's functionality. The vulnerability affects all versions up to and including 4.19.0. As of this report, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the risk remains due to the plugin's widespread use in WordPress ecosystems.

Supply Chain & Package Security

This vulnerability is specific to the WordPress plugin ecosystem. The plugin is distributed via the official WordPress Plugin Directory and third-party marketplaces. Users are advised to monitor the plugin's page for updates and consider disabling the plugin until a patch is available. No known supply chain attacks have been linked to this CVE.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: None
• Integrity Impact: Low
• Availability Impact: None

Threat Level: Medium. The vulnerability allows unauthorized modification of data but does not expose sensitive information or cause denial of service. Exploitation requires no authentication, making it accessible to any remote attacker.

Deep Dive & Mechanics

The vulnerability resides in the Pinterest Automatic Pin plugin's access control mechanisms. The plugin likely exposes REST API endpoints or AJAX actions that fail to properly verify user permissions before executing sensitive operations. Specifically, functions related to pin scheduling, account management, or content publishing may be accessible without authentication.

Root Cause: The plugin uses wp_ajax_* hooks without corresponding wp_ajax_nopriv_* checks, or implements custom capability checks that are incorrectly configured. This allows unauthenticated users to trigger actions intended only for authenticated administrators.

Attack Vector: An attacker can send crafted HTTP requests to the vulnerable endpoints, bypassing authorization checks. For example, a POST request to /wp-admin/admin-ajax.php with a specific action parameter could trigger unauthorized pin creation or deletion.

Impact: Successful exploitation could lead to:

• Unauthorized creation or deletion of Pinterest pins.
• Modification of plugin settings.
• Potential data integrity issues in connected Pinterest accounts.

Vulnerable vs. Patched Code

Since no patch is available, the following is a hypothetical comparison based on common missing authorization patterns.

Vulnerable Code (wp-pinterest-automatic <= 4.19.0):

add_action('wp_ajax_pinterest_automatic_create_pin', 'pinterest_automatic_create_pin');
function pinterest_automatic_create_pin() {
    // No capability check
    $pin_data = $_POST['pin_data'];
    // Process pin creation...
}

Patched Code (Hypothetical):

add_action('wp_ajax_pinterest_automatic_create_pin', 'pinterest_automatic_create_pin');
add_action('wp_ajax_nopriv_pinterest_automatic_create_pin', 'pinterest_automatic_create_pin');
function pinterest_automatic_create_pin() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    $pin_data = $_POST['pin_data'];
    // Process pin creation...
}

The patch adds a capability check (current_user_can('manage_options')) and ensures the action is only available to authenticated users with proper permissions.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A WordPress instance with Pinterest Automatic Pin plugin <= 4.19.0 installed and activated.
• Network access to the target.

Exploitation Steps:

1. Identify vulnerable endpoints by analyzing the plugin's source code or using fuzzing tools.
2. Send a crafted HTTP request to trigger unauthorized action. Example using curl:

   curl -X POST http://target.com/wp-admin/admin-ajax.php \
        -d 'action=pinterest_automatic_create_pin&pin_data={"title":"Test","image":"http://evil.com/malicious.jpg"}'
   

3. Verify the action was performed (e.g., a new pin appears in the plugin's dashboard).

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team

Detection & Response:

• Monitor for unusual AJAX requests to /wp-admin/admin-ajax.php with actions prefixed by pinterest_automatic_.
• Alert on requests from unauthenticated users to these endpoints.
• Review plugin logs for unauthorized pin creation or deletion events.
• Implement Web Application Firewall (WAF) rules to block suspicious requests.

Honeypot Setup:

• Deploy a decoy WordPress instance with the vulnerable plugin to capture attacker behavior.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action=pinterest_automatic_* parameters.
  • Unusual user agents or IP addresses targeting the plugin's endpoints.
• File IOCs:
  • Modified plugin files (e.g., wp-content/plugins/wp-pinterest-automatic/*.php).
  • Unexpected entries in plugin logs.
• Behavioral IOCs:
  • Unauthorized Pinterest pins appearing in the connected account.
  • Changes to plugin settings without admin interaction.

Detection Engineering

YARA Rule

rule CVE_2025_39511_Missing_Auth {
    meta:
        description = "Detects missing authorization in Pinterest Automatic Pin plugin"
        author = "Valters IT"
        date = "2025-04-01"
        cve = "CVE-2025-39511"
    strings:
        $vuln_func = "pinterest_automatic_" ascii wide nocase
        $ajax_hook = "wp_ajax_" ascii wide nocase
        $no_check = "current_user_can" ascii wide nocase
    condition:
        $vuln_func and $ajax_hook and not $no_check
}

Sigma Rule

title: CVE-2025-39511 - Missing Authorization in Pinterest Automatic Pin
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects unauthorized AJAX requests to Pinterest Automatic Pin plugin
author: Valters IT
date: 2025-04-01
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=pinterest_automatic_'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: medium

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2025-39511 - Pinterest Automatic Pin Missing Authorization";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-ajax.php";
    http_uri;
    content:"action=pinterest_automatic_";
    http_client_body;
    sid:1000001;
    rev:1;
    priority:2;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released.
2. Implement virtual patching via WAF rules to block requests to /wp-admin/admin-ajax.php with action=pinterest_automatic_* parameters from unauthenticated users.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the official patch once released by ValvePress.
• If custom development is possible, add capability checks to all AJAX actions as shown in the patched code example.

Workaround:

• Restrict access to /wp-admin/admin-ajax.php using .htaccess or server-level rules for unauthenticated users (note: this may break legitimate functionality).

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert
Report generated for CVE-2025-39511