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Critical 9.2Published Jul 6, 2026

CVE-2026-42341FOSSBilling has an unauthenticated payment bypass via IPN callback forgery

Updated under an hour ago ()

Does this affect you?

It affects FOSSBilling. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

FOSSBilling 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.

CVSS
9.2 CRITICAL (v4.0, CNA)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
Weakness (CWE)
CWE-306, CWE-346
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Jul 7, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
FOSSBilling FOSSBilling
fossbilling:fossbilling (from the name)
from 0.6.0, < 0.8.0
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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CVE-2026-42341: FOSSBilling has an unauthenticated payment bypass via IPN callback forgery | InfoSec Signals