CVE intelligence and bounded remediation

CVE-2026-33734 — FOSSBilling is a free, open-source billing and client management system

Medium CVSS 6.9

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.

Severity
Medium
CVSS
6.9 (4.0)
Published
2026-07-06
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-89

Affected products

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Matched remediation archetype

SQL and data-query injection

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Check exposure

  • Trace request, message, file, and stored values into SQL, ORM query fragments, filters, sort expressions, and other data-query languages.
  • Inventory database roles, reachable schemas, multi-tenant boundaries, and whether stacked or administrative operations are enabled.
  • Check both direct queries and second-order use of previously stored values.

Remediate safely

  • Use parameterized queries or safe query builders for all values; map identifiers and operators through explicit allowlists.
  • Remove raw query concatenation and give the application account only the tables and operations it requires.
  • Update affected data-access components and add regression tests for query structure preservation with inert edge-case inputs.

Authoritative sources

Complete CVE record and remediation plan

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