The Payment Integration Wompi WordPress plugin through 4.0.1 does not verify the authenticity of incoming payment notifications on a stock install, because the callback's checksum is keyed on a merchant secret that is empty until it is manually configured, allowing an unauthenticated attacker to forge a notification and mark an arbitrary order as paid.

The Payment Integration Wompi WordPress plugin through 4.0.1 does not verify the authenticity of incoming payment notifications on a stock install, because the callback's checksum is keyed on a merchant secret that is empty until it is manually configured, allowing an unauthenticated attacker to forge a notification and mark an arbitrary order as paid.