FOSSBilling has an unauthenticated payment bypass via IPN callback forgery

Summary

CVECVE-2026-42341
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-06 21:16:55 UTC
Updated2026-07-07 16:16:39 UTC
DescriptionFOSSBilling is a free, open-source billing and client management system. Versions 0.6.0 through 0.7.2 have an unauthenticated payment bypass vulnerability in FOSSBilling's IPN callback endpoint. When the Custom payment adapter is enabled, an attacker can mark any unpaid invoice as paid and credit the associated client account without making an actual payment, by sending a single crafted HTTP request. Version 0.8.0 patches the issue. Some workarounds are available. Disable the Custom payment gateway if not actively needed and/or restrict access to `/ipn.php` at the web server level (e.g., via IP allowlisting), noting that this may interfere with legitimate payment callback processing.

Risk And Classification

Primary CVSS: v4.0 9.2 CRITICAL from [email protected]

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/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

Problem Types: CWE-306 | CWE-346 | CWE-306 CWE-306: Missing Authentication for Critical Function | CWE-346 CWE-346: Origin Validation Error


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary9.2CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N/E:X/C...
4.0CNADECLARED9.2CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
High
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA FOSSBilling FOSSBilling affected >= 0.6.0, < 0.8.0 Not specified

References

ReferenceSourceLinkTags
github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-5493-9m76-2qrr [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis
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