---
cve: "CVE-2026-43927"
severity: "MEDIUM"
cvss: 6.9
epss: "0.3%"
vendor: "fossbilling"
kev: false
exploited: false
published: "2026-07-06 21:49:26"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T09:23:14+02:00"
---

# CVE-2026-43927

> 6.9 MEDIUM · 🧪 PoC

## Beschreibung

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-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 3bd35f5b2921d8a26a403142ae0408f95e6463cc (Commit)

## Referenzen

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

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-43927) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_