Unauthenticated payment bypass via unvalidated PayPal IPN
Published Aug 12, 2026 · Updated Aug 12, 2026
Payment verification failure in Quick Paypal Payments through 5.7.50 allows remote attackers to mark underpaid orders as paid via PayPal IPN. The IPN handler accepts a matching custom order token without comparing the paid amount, currency, receiver, or completed-payment status with the stored order. Exploitation requires a published priced form using PayPal Standard, and a genuine underpayment can trigger confirmation and fulfillment as though the full price were received.
Summary
What happened
Payment verification failure in Quick Paypal Payments through 5.7.50 allows remote attackers to mark underpaid orders as paid via PayPal IPN. The IPN handler accepts a matching custom order token without comparing the paid amount, currency, receiver, or completed-payment status with the stored order. Exploitation requires a published priced form using PayPal Standard, and a genuine underpayment can trigger confirmation and fulfillment as though the full price were received.
The record
- CVE
- CVE-2026-17008
- Published
- Aug 12, 2026
- Updated
- Aug 12, 2026
- Vendor
- Fullworks Digital Ltd.
- Product
- Quick PayPal Payments
- Classifications
- CWE-345, T1565.001
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 12, 2026CVE publishedPublication date reported by the CVE source.
- Aug 12, 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 <=5.7.50
What conditions does exploitation require?
What is affected?
Published CVSS scores
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
- WPScan PayPal IPN underpayment proof of conceptfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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