Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M

CVE-2026-43925FOSSBilling: Mass assignment of group_id in guest client registration allows unauthorized promo code use

Medium 6.9

In plain English

A medium-severity security flaw in FOSSBilling from FOSSBilling. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).

Severity (CVSS 4.0)6.9Medium
Exploit odds (30 days)0.5%top 59.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

FOSSBilling is a free, open-source billing and client management system. Prior to version 0.8.0, an unauthenticated mass assignment vulnerability in the client self-registration endpoint allows any visitor to assign themselves to an arbitrary client group during sign-up. Because client groups can gate promo code eligibility, an attacker may apply group-restricted discount codes and receive unauthorized discounts. Version 0.8.0 contains a patch. As a workaround, administrators can either remove group restrictions from promo codes or disable client self-registration (Settings → Clients → Disable signup).

Affected products (as reported)

VendorProductVersions
FOSSBilling FOSSBilling < 0.8.0

Weakness: CWE-915 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

References