The Mollie webhook endpoint accepts two independent, attacker-controlled parameters and never verifies that they belong together:
* commerceTransactionHash — selects which Craft Commerce transaction is completed
* id — selects which Mollie payment is queried for its status
An unauthenticated attacker holding any paid Mollie payment ID from the merchant’s account can pair it with any transaction hash.
Commerce queries Mollie, sees status: paid, and marks the target transaction successful for that transaction’s full
amount, regardless of how much was actually paid.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://github.com/craftcms/commerce-mollie
7004884b-51e2-48e8-b4a2-5ca29e80453e
https://github.com/craftcms/commerce-mollie/releases/tag/4.4.3
7004884b-51e2-48e8-b4a2-5ca29e80453e
https://github.com/craftcms/commerce-mollie/security/advisories/GHSA-3qcx-mjf6-…
7004884b-51e2-48e8-b4a2-5ca29e80453e
https://www.hckrt.com/hacktivity/HCKRT-6RB2BC
7004884b-51e2-48e8-b4a2-5ca29e80453e