AUGUST 25, 2026
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Case File

CVE-2026-42331

HIGH · CVSS 7.7 EPSS 0.25% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-06 · Last synced 2026-08-05

CyberRota Analysis

AI-Generated

The Guest API invoice/update endpoint in FOSSBilling versions prior to 0.8.0 lacks an authorization check, allowing unauthenticated users to modify the payment gateway for unpaid invoices if they possess the invoice hash. This vulnerability could lead to unauthorized changes in payment processing, potentially impacting financial transactions. Organizations using affected versions should prioritize upgrading to version 0.8.0 or later to mitigate this risk, especially those with publicly accessible invoice links.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-42331
Severity
HIGH
CVSS
7.7
EPSS
0.25%

Original NVD 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.