CVE-2026-42331Public exploitNetwork attack vector

Unauthenticated invoice gateway changes via omitted authorization

Published Jul 6, 2026 · Updated Jul 6, 2026

Incorrect authorization in FOSSBilling before 0.8.0 allows remote attackers with an invoice hash to change an unpaid invoice's gateway. The Guest Invoice API update and payment methods omit the checkInvoiceAuth() call used by get, so they process hash and gateway_id inputs without enforcing the invoice access policy. Exploitation requires a valid invoice hash and an administrator-configured gateway; it can alter the gateway or expose adapter output but cannot target an arbitrary external payment endpoint.

CVSS severity7.7
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in FOSSBilling before 0.8.0 allows remote attackers with an invoice hash to change an unpaid invoice's gateway. The Guest Invoice API update and payment methods omit the checkInvoiceAuth() call used by get, so they process hash and gateway_id inputs without enforcing the invoice access policy. Exploitation requires a valid invoice hash and an administrator-configured gateway; it can alter the gateway or expose adapter output but cannot target an arbitrary external payment endpoint.

The record

CVE
CVE-2026-42331
Published
Jul 6, 2026
Updated
Jul 6, 2026
Vendor
FOSSBilling
Product
FOSSBilling
Classifications
CWE-863, CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FOSSBilling · FOSSBillingversion=< 0.8.0

Published CVSS scores

7.7GitHub, Inc.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

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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