CVE-2026-33734

MEDIUMCVSS 6.9/10EPSS 0.22%

Last modified

CVE-2026-33734 is a medium-severity vulnerability rated 6.9/10 on the CVSS scale. 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. EPSS estimates a 0.22% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 4.0
6.9/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.22%

12.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
FOSSBillingFOSSBilling>= 0.6.0, < 0.8.0

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-33734?
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.
How severe is CVE-2026-33734?
CVE-2026-33734 has a CVSS score of 6.9/10 (MEDIUM severity). The EPSS model estimates a 0.22% probability of exploitation in the next 30 days.
How do I fix CVE-2026-33734?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST