PT-2026-56031 · Fossbilling · Fossbilling

Dilipmallavarapu · Published 2026-07-06 · Updated 2026-07-06 · CVE-2026-43927

Mitre

CVSS v4.0

6.9

Medium

Base vector

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

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.

Fix

Time Of Check To Time Of Use

Weakness Enumeration

CWE-367

Related Identifiers

CVE-2026-43927

Affected Products

Fossbilling

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-43927 · Security Note
• https://github.com/FOSSBilling/FOSSBilling/security/advisories/GHSA-w898-cx35-25gh · Note