CVE-2026-43921
Admin-authenticated RCE: injects PHP into config.php, executed on every request.
Is CVE-2026-43921 being exploited?
Not confirmed. CVE-2026-43921 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.43% probability of exploitation in the next 30 days.
How severe is CVE-2026-43921?
CVE-2026-43921 is rated High with a CVSS score of 8.9. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-43921?
Yes. A fix has been recorded for CVE-2026-43921. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-43921 affect?
CVE-2026-43921 affects FOSSBilling 0.6.10-0.7.2. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-43921?
Upgrade to 0.8.0; restrict admin access; audit config.php.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
RCE via admin config changes; attacker can run PHP on the server on each request.
Patch when possible
- affected>= 0.6.10 and < 0.8.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.