Vulnerability · Published Jul 6, 2026 · Assigned by GitHub_M
CVE-2026-33734FOSSBilling has improper SQL neutralization in `Massmailer` recipient filters
Medium 6.9
In plain English
A medium-severity SQL injection in FOSSBilling from FOSSBilling. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official description
FOSSBilling is a free, open-source billing and client management system. Versions 0.6.0 through 0.7.2 have a SQL injection vulnerability in the `Massmailer` module filter functionality. An authenticated administrator can supply crafted filter values when updating a mass email message, causing untrusted input to be interpolated directly into SQL in the recipient selection query. Version 0.8.0 patches the issue. Some workarounds are available. Restrict administrator access to trusted users only, disable the `Massmailer` module if it is not required, audit existing records in the `mod_massmailer` table for suspicious filter values, and/or review administrator activity related to `Massmailer` message updates.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| FOSSBilling | FOSSBilling | >= 0.6.0, < 0.8.0 |
Weakness: CWE-89 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N