Answer in brief
CVE-2026-43928 records a Low severity (CVSS 2.3) vulnerability in FOSSBilling: Payment amount not validated in PayPalEmail adapter allows invoice underpayment. The current sources do not mark it as known exploited. The current feed maps FOSSBilling/FOSSBilling (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps FOSSBilling/FOSSBilling (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| FOSSBilling/FOSSBillinggeneric | < 0.8.0 | Not reported |
Published upstream
Jul 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-43928 records a Low severity (CVSS 2.3) vulnerability in FOSSBilling: Payment amount not validated in PayPalEmail adapter allows invoice underpayment. The current sources do not mark it as known exploited. The current feed maps FOSSBilling/FOSSBilling (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 2.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps FOSSBilling/FOSSBilling (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| FOSSBilling/FOSSBillinggeneric | < 0.8.0 | Not reported |
Published upstream
Jul 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 6, 2026
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.
Quoted source text, attributed separately from HOL analysis.