Payment Authentication Flaw in Quick Event Manager by WordPress
CVE-2026-121636

5.3MEDIUM

Key Information:

Vendor

WordPress
Status
Quick Event Manager
Vendor
CVE Published:
6 November 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-121636?

The Quick Event Manager plugin for WordPress, prior to version 9.19, has a vulnerability where it fails to verify the authenticity of PayPal payment notifications. This flaw allows unauthenticated attackers to manipulate the system, marking event registrations as paid without genuine payment being processed. Consequently, this could lead to unauthorized access to services that rely on valid payment confirmations, raising significant security and operational concerns for users of this plugin.

Affected Version(s)

Quick Event Manager 9.9.5 < 9.19

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-2026-121636 - Proof of Concept

References

https://wpscan.com/vulnerability/04b181e1-639c-476f-b66b-...
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

Naoki Kawahigashi
WPScan
.