CVE-2026-11964

CRITICAL9.1

User Registration & Membership < 5.2.2 - Unauthenticated PayPal Webhook Signature Verification Bypass Leading to Membership Activation

Published Jul 13, 2026

Modified 3 months ago

Details

The User Registration & Membership WordPress plugin before 5.2.2 does not verify the authenticity of incoming payment-provider webhook notifications before acting on them, allowing unauthenticated attackers to forge a payment-approved event and activate a paid membership subscription without completing a real payment.

References

DETECTION

https://wpscan.com/vulnerability/faf55649-8f76-4abf-a6b9-0d0774e22d29/

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-11964

CVSS Analysis

CVSS v3.1

9.1

Exploitability

Attack Vector

NetworkAV:N

Attack Complexity

LowAC:L

Privileges Required

NonePR:N

User Interaction

NoneUI:N

Scope

UnchangedS:U

Impact

Confidentiality

HighC:H

Integrity

HighI:H

Availability

NoneA:N

9.1/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Ecosystems

Timeline

PublishedJul 13, 2026

ModifiedJul 13, 2026