Unauthenticated payment bypass via unchecked Payflow return
Published Aug 12, 2026 · Updated Aug 12, 2026
Payment bypass in Payment Gateway for PayPal on WooCommerce before 9.2.1 allows remote attackers to mark arbitrary orders paid. The unauthenticated PayPal Advanced return handler trusts attacker-supplied INVOICE and PNREF values and completes an order even when its server-side Payflow inquiry fails. WooCommerce must be active, the gateway settings must exist, and an unpaid order ID must be known or guessed; exploitation changes that order to processing without payment.
Summary
What happened
Payment bypass in Payment Gateway for PayPal on WooCommerce before 9.2.1 allows remote attackers to mark arbitrary orders paid. The unauthenticated PayPal Advanced return handler trusts attacker-supplied INVOICE and PNREF values and completes an order even when its server-side Payflow inquiry fails. WooCommerce must be active, the gateway settings must exist, and an unpaid order ID must be known or guessed; exploitation changes that order to processing without payment.
The record
- CVE
- CVE-2026-16621
- Published
- Aug 12, 2026
- Updated
- Aug 12, 2026
- Vendor
- Easy Payment
- Product
- Payment Gateway for PayPal on WooCommerce
- Classifications
- CWE-345, CAPEC-385, T1190
- 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 <9.2.1
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 Advanced return-handler proof of conceptfunctional · validated
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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