What’s Vulnerable › Vulnerabilities
CVE-2026-11964: User Registration & Membership < 5.2.2 - Unauthenticated PayPal Webhook Signature Verification Bypass Leading to Membership Activation
- Severity: critical (CVSS 9.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-07-13 · updated 2026-07-13
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
- User Registration & Membership: before 5.2.2 — fixed in 5.2.2
How to fix
Upgrade to a fixed version: User Registration & Membership 5.2.2. Check the vendor advisory for mitigations.
References
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