waimai Super Cms 20150505 has a logic flaw allowing attackers to modify a price, before form submission, by observing data in a packet capture. By setting the index.php?m=gift&a=addsave credit parameter to -1, the product is sold for free.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-21503
Reference (s):
- https://github.com/caokang/waimai/issues/15