CVE-2026-88764 Simple Membership < 4.7.8 - Subscriber+ Membership Level Escalation via PayPal Standard subsc_ref
Attackers can escalate membership privileges by manipulating PayPal payment notifications, bypassing intended access controls in the Simple Membership plugin.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-88764?
CVE-2026-88764 is a medium-severity vulnerability in Unknown Simple Membership, published on 13 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-269
Which versions are affected by CVE-2026-88764?
How do I fix CVE-2026-88764?
No fix has been published for CVE-2026-88764 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-88764 being exploited?
There is no known exploitation of CVE-2026-88764 in the wild and no public exploit code.
Sources
Also known as GHSA-cmhf-4mfx-3gf7.