Unauthorized Payment Confirmation in WP Express Checkout Plugin
CVE-2026-83537

5.3MEDIUM

Key Information:

Vendor

WordPress
Status
WP Express Checkout
Vendor
CVE Published:
9 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-83537?

The WP Express Checkout plugin for WordPress prior to version 2.5.0 is susceptible to a significant security flaw that fails to properly validate the completion of payment transactions on the server-side. This oversight allows unauthorized users to simulate the payment process, marking orders as completed without actually making any payments. Such a vulnerability puts both merchants and customers at risk, emphasizing the need for robust checks to ensure transaction integrity and prevent fraudulent activities.

Affected Version(s)

WP Express Checkout 0 < 2.5.0

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-83537 - Proof of Concept

References

https://wpscan.com/vulnerability/02b39e4f-181d-4573-9175-...
exploitvdb-entrytechnical-description

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ryan zegar
WPScan
.