Critical severity · published Aug 7, 2026
CVE-2026-16038
MStore API < 4.21.0 - Unauthenticated Payment Bypass via Multiple Payment Gateways
9.1
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 36% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MA
MStore API ·
before 4.21.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-16038
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-16038
wpscan.com
https://wpscan.com/vulnerability/6321d247-39c7-43a6-a528-202e1118a5d5/
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