Vulnerability · Published Jul 13, 2026 · Assigned by WPScan
CVE-2026-11964User Registration & Membership < 5.2.2 - Unauthenticated PayPal Webhook Signature Verification Bypass Leading to Membership Activation
Critical 9.1
In plain English
A critical-severity security flaw in User Registration & Membership from Unknown. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 60.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Unknown | User Registration & Membership | 0 – before 5.2.2 |
References
- https://wpscan.com/vulnerability/faf55649-8f76-4abf-a6b9-0d0774e22d29/ exploit, vdb-entry, technical-description