Membership escalation via unchecked PayPal subscription reference
Published Sep 13, 2026 · Updated Sep 13, 2026
Improper payment validation in wp.insider Simple Membership before 4.7.8 allows remote authenticated users to obtain higher membership access. The PayPal Standard IPN handler trusts the submitted subscr_ref membership level without checking it against the level assigned to the paid button. A member can pay for a lower-priced button and receive the access rights of a more privileged membership level.
Summary
What happened
Improper payment validation in wp.insider Simple Membership before 4.7.8 allows remote authenticated users to obtain higher membership access. The PayPal Standard IPN handler trusts the submitted subscr_ref membership level without checking it against the level assigned to the paid button. A member can pay for a lower-priced button and receive the access rights of a more privileged membership level.
The record
- CVE
- CVE-2026-88764
- Published
- Sep 13, 2026
- Updated
- Sep 13, 2026
- Vendor
- WP Affiliate Manager
- Product
- Simple Membership
- Classifications
- T1098
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 13, 2026CVE publishedPublication date reported by the CVE source.
- Sep 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <4.7.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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