CVE-2026-88764: Unknown Simple Membership

Medium severity, CVSS 5.4. EPSS: 0.2% chance of exploitation in the next 30 days.

The Simple Membership WordPress plugin before 4.7.8 does not validate that the membership level supplied in a PayPal payment notification matches the level configured for the paid payment button, allowing members to pay for a lower-priced membership while being granted a higher, more privileged membership level.

Affected products

• Unknown Simple Membership: before 4.7.8 (fixed in 4.7.8)

Published 2026-09-13. Last modified 2026-09-14.