CVE-2026-18233: Unknown Mstore API

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

The MStore API WordPress plugin before 4.21.1 does not verify that the order targeted by one of its delivery endpoints belongs to the requester, allowing any authenticated user, including Subscribers, to mark arbitrary orders as completed and paid without any payment being made.

Affected products

• Unknown Mstore API: before 4.21.1 (fixed in 4.21.1)

Published 2026-08-29. Last modified 2026-08-31.