Webhook Authentication Flaw in User Registration & Membership Plugin for WordPress
CVE-2026-11964

9.1CRITICAL

Key Information:

Vendor

WordPress
Status
User Registration & Membership
Vendor
CVE Published:
13 July 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-11964?

The User Registration & Membership plugin for WordPress prior to version 5.2.2 is vulnerable due to inadequate validation of incoming payment notifications from providers. This flaw allows an attacker to bypass payment verification and artificially trigger paid membership subscriptions, potentially leading to unauthorized access to premium content or features without actual payment.

Affected Version(s)

User Registration & Membership 0 < 5.2.2

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-2026-11964 - Proof of Concept

References

https://wpscan.com/vulnerability/faf55649-8f76-4abf-a6b9-...
exploitvdb-entrytechnical-description

CVSS V3.1

Score:
9.1
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
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

Alessandro Greco aka Aleff
Giovanbattista Ianni (University of Calabria - UNICAL)
WPScan
.