Simple Membership <= 4.7.5 - Missing Authorization to Unauthenticated Arbitrary Member Account Deactivation via Forged Stripe 'charge.refunded' Webhook
Affected versions: *-4.7.5
Vulnerability type: CWE-862 Missing Authorization
Affected software, patched versions and attribution
The Simple Membership plugin for WordPress is vulnerable to authorization bypass in all versions up to, and including, 4.7.5. This is due to the plugin not properly verifying that a user is authorized to perform an action. This makes it possible for unauthenticated attackers to deactivate arbitrary member accounts by forging a charge.refunded webhook event containing a victim's subscription ID, setting the target member's account_state to 'inactive' and triggering cancellation hooks, transaction-record status changes, and cancellation notification emails. This vulnerability is exploitable only on installations where no Stripe webhook signing secret has been configured, which is the default out-of-the-box state; sites that have configured the stripe-webhook-signing-secret option are routed to the properly verified HMAC path and are not affected.
Simple Membership
Affected versions: *-4.7.5
Patched versions: 4.7.6
Researcher credit: Nikita Fenko
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- Published
- June 17, 2026
- CVSS
- 5.3