CVE-2025-31063

Executive Summary

CVE-2025-31063 is a Missing Authorization vulnerability in the WordPress plugin Wishlist by redqteam, affecting versions up to and including 2.1.0. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or modification of wishlist entries. The vulnerability has a CVSS score of 4.3 (Medium) and an EPSS score of 0.0%, indicating low exploitation likelihood at this time. No public proof-of-concept (PoC) or patch is currently available.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor the plugin’s update channel for a patched version. Since no patch is available, consider disabling the plugin or implementing a Web Application Firewall (WAF) rule to block exploitation attempts.

CVSS Breakdown & Threat Level

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

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low integrity compromise (e.g., modifying wishlist data). No public exploit code exists, reducing immediate risk.

Deep Dive & Mechanics

The vulnerability resides in the Wishlist plugin’s REST API endpoints or AJAX handlers that fail to properly verify user permissions before processing requests. Specifically, functions that create, read, update, or delete wishlist items do not enforce capability checks (e.g., current_user_can()). This allows any unauthenticated user to send crafted HTTP requests to manipulate wishlist data belonging to other users.

Root Cause: The plugin uses wp_ajax_nopriv_* hooks without additional authorization checks, or implements custom nonce verification that can be bypassed. The missing current_user_can() or wp_verify_nonce() call enables unauthorized actions.

Attack Vector: An attacker sends a POST request to the vulnerable endpoint with parameters such as action, wishlist_id, product_id, etc. The server processes the request without verifying the user’s identity or ownership of the wishlist.

Vulnerable vs. Patched Code

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

Vulnerable Code (wishlist.php):

add_action('wp_ajax_nopriv_wishlist_add_item', 'wishlist_add_item');
function wishlist_add_item() {
    $product_id = intval($_POST['product_id']);
    // Missing authorization check
    $wishlist = get_user_wishlist(get_current_user_id());
    $wishlist->add_item($product_id);
    wp_send_json_success();
}

Patched Code (wishlist.php):

add_action('wp_ajax_nopriv_wishlist_add_item', 'wishlist_add_item');
function wishlist_add_item() {
    if (!is_user_logged_in()) {
        wp_send_json_error('Unauthorized', 403);
    }
    if (!wp_verify_nonce($_POST['_wpnonce'], 'wishlist_nonce')) {
        wp_send_json_error('Invalid nonce', 403);
    }
    $product_id = intval($_POST['product_id']);
    $wishlist = get_user_wishlist(get_current_user_id());
    $wishlist->add_item($product_id);
    wp_send_json_success();
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites: A WordPress site with Wishlist plugin version <= 2.1.0.

Exploit Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php).
2. Craft a POST request to add a product to another user’s wishlist:

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=wishlist_add_item&product_id=123&wishlist_id=456"

3. To read wishlist data, use:

curl -X POST http://target.com/wp-admin/admin-ajax.php \
  -d "action=wishlist_get_items&wishlist_id=456"

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

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual POST requests to /wp-admin/admin-ajax.php with action parameters containing wishlist_*.
• Look for requests without a valid _wpnonce parameter or with missing authentication cookies.

Defense:

• Disable the plugin until a patch is released.
• Implement a WAF rule to block requests to admin-ajax.php with action starting with wishlist_ from unauthenticated users.
• Use a security plugin (e.g., Wordfence) to enforce capability checks.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=wishlist_* parameters.
  • Repeated requests with varying wishlist_id or product_id values.
• File IOCs:
  • Modified wishlist entries in the database (e.g., wp_wishlist_items table).
• Log IOCs:
  • PHP error logs showing Undefined index: _wpnonce or similar warnings.

Detection Engineering

YARA Rule

rule CVE_2025_31063_Wishlist_Exploit {
    meta:
        description = "Detects exploitation attempts of CVE-2025-31063 in WordPress Wishlist plugin"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2025-31063"
    strings:
        $ajax = "admin-ajax.php" nocase
        $action = "action=wishlist_" nocase
        $product = "product_id=" nocase
        $wishlist = "wishlist_id=" nocase
    condition:
        all of them
}

Sigma Rule

title: CVE-2025-31063 Wishlist Plugin Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthorized access to Wishlist plugin endpoints
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=wishlist_'
    condition: selection
falsepositives:
    - Legitimate plugin usage by authenticated users
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-31063 Wishlist Plugin Exploitation Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=wishlist_"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patched version is released.
2. Implement a WAF rule to block unauthenticated requests to admin-ajax.php with action parameters starting with wishlist_.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply the vendor patch when available (check the WordPress plugin repository).
• If the plugin is abandoned, consider migrating to an alternative wishlist plugin with active security maintenance.

Workaround:

• Add a custom function to your theme’s functions.php to enforce authorization:

add_action('wp_ajax_nopriv_wishlist_add_item', function() {
    wp_send_json_error('Unauthorized', 403);
}, 1);

Valters IT
Securing Digital Frontiers