dbcve.org
Code InjectionWeakness · CWE-94

CVE-2026-43921

HIGH · 8.9 CVSS v4.0 Published 2026-07-06
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable Zero-click 7 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
FOSSBilling is a free, open-source billing and client management system. Versions 0.6.10 through 0.7.2 have a PHP code injection vulnerability in FOSSBilling's `Config::prettyPrintArrayToPHP()` method. When configuration values are updated, string values are written into `config.php` without escaping single quotes. Because `config.php` is loaded via a bare `include` on every HTTP request, an attacker with admin privileges can inject arbitrary PHP code that executes on every subsequent request. Version 0.8.0 contains a patch. Some workarounds are available. Restrict admin access to trusted personnel only; audit `config.php` for unexpected PHP code; and/ or at the reverse proxy/WAF level, restrict access to admin API endpoints that modify configuration.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

FOSSBilling versions 0.6.10-0.7.2 contain a PHP code injection vulnerability in the Config::prettyPrintArrayToPHP() method. When admin users update configuration values, string inputs are written to config.php without proper escaping of single quotes. Since config.php is included via a bare include() on every HTTP request, injected PHP code executes persistently on every subsequent request.

MitigationApply the vendor patch in version 0.8.0. As immediate workarounds, restrict admin access to trusted personnel only, audit config.php for unauthorized PHP code, and implement WAF/reverse proxy controls on admin API endpoints that modify configuration.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
High
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify FOSSBilling version
    Locate the version file or check the admin dashboard footer for the installed FOSSBilling version number
    Affected if version is 0.6.10 through 0.7.2 inclusive
  2. Locate Config.php class file
    Search the FOSSBilling source code for a file containing the Config class definition, typically in src/ or includes/ directories
    Affected if the prettyPrintArrayToPHP() method exists in the codebase (vulnerable method present)
  3. Inspect config.php for injected code
    Open the configuration file (usually at includes/config.php or similar path) and search for any eval(), system(), shell_exec(), or suspicious PHP code blocks that were not intentionally added
    Affected if config.php contains unexpected PHP code, especially code with single quotes that could have been injected through the vulnerable method
  4. Verify admin access exposure
    Check if the admin interface is accessible to untrusted users or if admin API endpoints handling configuration updates are exposed without proper authentication
    Affected if untrusted or anonymous users can access admin configuration functionality (prerequisite for exploitation)

You are affected if FOSSBilling version is between 0.6.10-0.7.2 and the prettyPrintArrayToPHP method exists in your codebase, or if your config.php file contains unauthorized PHP code injections.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor patch in version 0.8.0. As immediate workarounds, restrict admin access to trusted personnel only, audit config.php for unauthorized PHP code, and implement WAF/reverse proxy controls on admin API endpoints that modify configuration.

Recommended fix High confidence

FOSSBilling version 0.8.0

  1. Upgrade FOSSBilling from any version between 0.6.10 and 0.7.2 to version 0.8.0 which contains the patch for this vulnerability
  2. After upgrading, immediately audit the config.php file for any unexpected or malicious PHP code that may have been injected prior to the upgrade
  3. Review admin access logs for any suspicious activity that may indicate exploitation attempts
  4. As a defensive measure, restrict admin panel access to only trusted personnel and consider implementing IP allowlisting at the reverse proxy or WAF level for admin API endpoints that modify configuration

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-43921 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data