{"cve":"CVE-2026-42331","nvd":{"published":"2026-07-06T21:16:55.617","modified":"2026-07-07T15:16:46.967","status":"Deferred","description":"FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, the Guest API invoice/update endpoint is missing an authorization check present in other invoice-related endpoints, allowing an unauthenticated user with knowledge of an invoice hash to modify the payment gateway associated with an unpaid invoice. An attacker who obtains an invoice hash, which may leak through shared URLs, referrer headers, or email links,  can change the `gateway_id` on an unpaid invoice to any payment gateway configured in the system. This does not allow redirecting payments to an arbitrary external endpoint, as the gateway must already be installed and configured by an administrator. The practical impact is further limited by the `invoice_accessible_from_hash` system setting. Version 0.8.0 contains a patch. No known workarounds are available.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:H/SA:N","score":7.7},"cvss_v3":null,"cwes":["CWE-306","CWE-863"],"references":["https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-8755-w77f-3g7j","https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-8755-w77f-3g7j"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:42:16.820116992+00:00"},"epss":{"cve":"CVE-2026-42331","score":0.00419,"percentile":0.36215,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}