CVE-2026-43927 FOSSBilling has race condition in cart checkout that bypasses promo code usage limits
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-43927?
CVE-2026-43927 is a medium-severity vulnerability in FOSSBilling, published on 6 Jul 2026.
Official 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.
Weakness: CWE-367
Which versions are affected by CVE-2026-43927?
How do I fix CVE-2026-43927?
No fix has been published for CVE-2026-43927 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-43927 being exploited?
There is no known exploitation of CVE-2026-43927 in the wild and no public exploit code.
Sources
Also known as GHSA-w898-cx35-25gh.