CVE-2026-18233: MStore API < 4.21.1 - Subscriber+ Arbitrary Order Completion
Noroxi assessment
Priority: Monitor (action score 26/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 0.29% (FIRST EPSS).
- Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Unknown MStore API 4.21.1.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to Unknown MStore API 4.21.1 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · FIRST EPSS
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.
- Published
- Aug 29, 2026
- Updated
- Aug 31, 2026
- EPSS
- 0.2% · 22th percentile
- CWE
- CWE-862
Report tools
Action score
26
Monitor
Low priority for now.
- CVSS
- 26 / 40 · 6.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
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Versions reported by the vendor
Affected version ranges reported by the assigning authority (WPScan). Independent of NVD's CPE analysis and usually ahead of it.
Unknown MStore API
- before 4.21.1affected · semver
Same product
unknown: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-16038MStore API < 4.21.0 - Unauthenticated Payment Bypass via Multiple Payment Gateways36Monitor
- CVE-2026-16030MStore API < 4.21.0 - Unauthenticated Account Takeover via Firebase Phone Authentication32Monitor
- CVE-2026-16041MStore API < 4.21.0 - Unauthenticated Product Review Creation30Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-16039Aug 7, 2026 · MStore API < 4.21.0 - Subscriber+ Order and Customer PII Disclosure via IDOR26Monitor
- Later →CVE-2026-18234Aug 29, 2026 · MStore API < 4.21.1 - Subscriber+ Arbitrary Order Payment Bypass via Wallet26Monitor
- Later →CVE-2026-97219Oct 2, 2026 · MStore API 4.21.1 - 4.22.0 - Subscriber+ Payment Bypass via 'status' Parameter17Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Unknown MStore API | 4.21.1 | Vendor (CNA) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- WPScancoordinator
- Erwan LR (WPScan)finder
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-1603822 days apartMStore API < 4.21.0 - Unauthenticated Payment Bypass via Multiple Payment Gateways36Monitor
- CVE-2026-1604122 days apartMStore API < 4.21.0 - Unauthenticated Product Review Creation30Monitor
- CVE-2026-182340 days apartMStore API < 4.21.1 - Subscriber+ Arbitrary Order Payment Bypass via Wallet26Monitor
- CVE-2026-9721934 days apartMStore API 4.21.1 - 4.22.0 - Subscriber+ Payment Bypass via 'status' Parameter17Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-26-0946 · Aug 31, 2026(WordPress Eklenti Güvenlik Bildirimi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- high · data or configuration can be modified
- Availability
- none
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- High
- Availability impact
- None
Weakness class (CWE)
CWE-862 · Missing AuthorizationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.