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Medium 6.9Published Jul 6, 2026

CVE-2026-43927FOSSBilling has race condition in cart checkout that bypasses promo code usage limits

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. Prior to version 0.8.0, a race condition in the cart checkout flow allows an authenticated client to apply a promo code beyond its configured maximum uses. By sending concurrent checkout requests before any single request completes the usage increment, a client can obtain unlimited discounted or free orders from a single-use or limited-use promo code. Version 0.8.0 patches the issue. Some workarounds are available. Disable promo codes entirely until a patch is available or monitor the `promo` table for `used` values exceeding `maxuses` and manually review affected orders.

CVSS
6.9 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Weakness (CWE)
CWE-367
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)
before 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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