2.3

CVE-2026-43928

FOSSBilling: Payment amount not validated in PayPalEmail adapter allows invoice underpayment

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.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
HerstellerFOSSBilling
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Produkt FOSSBilling
Version < 0.8.0
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.27% 0.192
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 2.3 0 0
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CWE-1284 Improper Validation of Specified Quantity in Input

The product receives input that is expected to specify a quantity (such as size or length), but it does not validate or incorrectly validates that the quantity has the required properties.

CWE-754 Improper Check for Unusual or Exceptional Conditions

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

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