Executive brief
# 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`
Affected products
- Packagist openmage/magento-lts