CVE-2026-43928

FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the PayPalEmail payment adapter accepts PayPal IPN callbacks and credits the IPN-supplied amount (`mc_gross`) to the client's balance without validating it against the invoice total. Combined with a $0.05 floating-point epsilon tolerance in the invoice credit-payment logic, this allows a client to underpay an invoice by up to $0.04 and still have it marked as fully paid. Version 0.8.0 patches the issue. There is no effective workaround without modifying the source code. Merchants using the PayPalEmail adapter should monitor IPN transactions for amounts that do not match their corresponding invoice totals, and manually review and refund suspicious payments.

CVSS

No CVSS.

References

Link	Resource
https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-xjc6-g382-h942
https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-xjc6-g382-h942

Configurations

No configuration.

History

07 Jul 2026, 14:16

Type	Values Removed	Values Added
References	~~() https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-xjc6-g382-h942 -~~	() https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-xjc6-g382-h942 -

06 Jul 2026, 22:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-06 22:16

Updated : 2026-07-07 14:16

NVD link : CVE-2026-43928

Mitre link : CVE-2026-43928

CVE.ORG link : CVE-2026-43928

JSON object : View

Products Affected

No product.

CWE

CWE-754

Improper Check for Unusual or Exceptional Conditions

CWE-1284

Improper Validation of Specified Quantity in Input

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