CVE-2026-40098

Description

# Cross-user wishlist item import via shared wishlist code, leading to private option disclosure and file-disclosure variant ## Summary The shared wishlist add-to-cart endpoint authorizes access with a public `sharing_code`, but loads the acted-on wishlist item by a separate global `wishlist_item_id` and never verifies that the item belongs to the shared wishlist referenced by that code. This lets an attacker use: - a valid shared wishlist code for wishlist A - a wishlist item ID belonging to victim wishlist B to import victim item B into the attacker's cart through the shared wishlist flow for wishlist A. Because the victim item's stored `buyRequest` is reused during cart import, the victim's private custom-option data is copied into the attacker's quote. If the product uses a file custom option, this can be elevated to cross-user file disclosure because the imported file metadata is preserved and the download endpoint is not ownership-bound. ## Vulnerability Type - Broken object-level authorization / IDOR - Cross-user data disclosure - Cross-user file disclosure variant ## Root Cause In `app/code/core/Mage/Wishlist/controllers/SharedController.php`, the shared flow does: ```php $item = Mage::getModel('wishlist/item')->load($itemId); $wishlist = Mage::getModel('wishlist/wishlist')->loadByCode($code); ... $item->addToCart($cart); ``` Relevant lines: - `SharedController.php:86` loads the wishlist item by global ID - `SharedController.php:87` loads the wishlist by shared code - `SharedController.php:99` imports the item into cart There is no check that: ```php $item->getWishlistId() == $wishlist->getId() ``` The safe owner flow in `app/code/core/Mage/Wishlist/controllers/IndexController.php:521-528` does preserve this binding by deriving the wishlist from `item->getWishlistId()`. The imported item keeps its original `buyRequest` because `app/code/core/Mage/Wishlist/Model/Item.php:370-372` passes that stored request directly into: ```php $cart->addProduct($product, $buyRequest); ``` ## Security Impact ### Baseline impact An attacker can import another user's private wishlist item into the attacker's own cart, using an unrelated shared wishlist code. This is a clear cross-user authorization bypass. The victim item's private configuration is copied into the attacker's quote, including custom-option values such as personalized text. ### Stronger variant: cross-user file disclosure If the victim item contains a custom option of type `file`, the imported quote item preserves file metadata such as: - `quote_path` - `order_path` - `secret_key` The file option renderer in `app/code/core/Mage/Catalog/Model/Product/Option/Type/File.php:547-552` generates a download URL from: - the imported `sales/quote_item_option` ID - the preserved `secret_key` The downloader in `app/code/core/Mage/Sales/controllers/DownloadController.php:150-185`: - loads quote item option by global ID - verifies only product option type and `secret_key` - reads the file from `order_path` or `quote_path` It does not verify ownership of the quote item, order, or original wishlist item. This creates a cross-user file disclosure path once victim file metadata has been imported. ## Steps To Reproduce ### Lab data - shared wishlist A: - `wishlist_id = 1` - `customer_id = 2` - `sharing_code = 6376bb8c37a09c2de3664bd8cdc16412` - victim wishlist B: - `wishlist_id = 2` - `customer_id = 3` - victim item: - `wishlist_item_id = 1` - `wishlist_id = 2` - `product_id = 2` - victim private text option marker: - `VICTIM-MARKER-49040822` ### Reproduction Send: ```http GET /wishlist/shared/cart/?code=6376bb8c37a09c2de3664bd8cdc16412&item=1 ``` Where: - `code` belongs to shared wishlist A - `item=1` belongs to victim wishlist B ### Expected result The request should be rejected because the item does not belong to the shared wishlist referenced by the `sharing_code`. ### Actual result The application imports victim item `1` into the attacker's quote anyway. ## Verified Evidence ### Baseline variant Previously verified at quote/option level in lab: ```text option_1 = VICTIM-MARKER-49040822 ``` This shows that the attacker's cart received victim-private custom-option data from another user's wishlist item. ### File-disclosure variant Previously verified in lab after importing a victim file-option payload: ```text /sales/download/downloadCustomOption/id/9/key/86fca9b61c0b891b52fb/ ``` This URL was generated from imported quote item option data containing the victim file metadata and secret key. ## Why This Is A Valid Bug This is not a timing issue and does not depend on non-default security settings. The bug is a direct authorization failure: - authorization is based on wishlist A's share code - the acted-on object is item B from another wishlist - there is no item-to-wishlist binding check - victim-controlled item state is then copied into attacker-controlled cart state That is a broken object-level authorization issue with clear cross-user impact. ## Remediation In `SharedController::cartAction()`, reject any request where the loaded item does not belong to the wishlist loaded from the share code: ```php $item = Mage::getModel('wishlist/item')->load($itemId); $wishlist = Mage::getModel('wishlist/wishlist')->loadByCode($code); if (!$item->getId() || !$wishlist->getId() || (int) $item->getWishlistId() !== (int) $wishlist->getId()) { return $this->_forward('noRoute'); } ``` Defense in depth: - bind `sales/download/downloadCustomOption` to the current quote/order owner instead of trusting only `id + secret_key`