CVE-2026-43927

medium

Description

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.

References

https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-w898-cx35-25gh

Details

Source: Mitre, NVD

Published: 2026-07-06

Updated: 2026-07-06

Risk Information

CVSS v2

Base Score: 4.9

Vector: CVSS2#AV:N/AC:M/Au:S/C:P/I:N/A:P

Severity: Medium

CVSS v3

Base Score: 8.1

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Severity: High

CVSS v4

Base Score: 6.9

Vector: 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