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TI-2026-13422 Aliases CVE-2026-16038GHSA-5xp8-jj53-535m

MStore API < 4.21.0 - Unauthenticated Payment Bypass via Multiple Payment Gateways

Priority HIGH 80CWE-862Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-862.

Summary

The MStore API WordPress plugin before 4.21.0 does not verify the payment with the payment gateway before marking an order as paid on several of its payment-completion endpoints, allowing an unauthenticated attacker to mark an arbitrary order fully paid without paying and obtain goods or services for free.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00418 36th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed MStore API (Unknown): 4.21.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
UnknownMStore APIbefore 4.21.04.21.0Patch availableCNA
  • MStore API VendorUnknown Affected before 4.21.0 Fixed in 4.21.0 Patch available CNA

Remediation

  • Fix · CNA MStore API (Unknown) Fixed in 4.21.0

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    MStore API 4.21.0

    4 records Highest priority Priority HIGH 2 HIGH, 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-13424 MStore API < 4.21.0 - Unauthenticated Product Review CreationPriority HIGH 72
    • TI-2026-13423 MStore API < 4.21.0 - Subscriber+ Order and Customer PII Disclosure via IDORPriority MEDIUM 62
    • TI-2026-13416 MStore API < 4.21.0 - Unauthenticated Account Takeover via Firebase Phone AuthenticationPriority LOW 37
    Show all 4 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-16038
  2. 2026-10-03 Alias added: GHSA-5xp8-jj53-535m

References

Exploit 1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences