CVE-2026-33543
Unauthenticated admin creation via flawed guest API in FOSSBilling <=0.7.2
Is CVE-2026-33543 being exploited?
Not confirmed. CVE-2026-33543 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 0.45% probability of exploitation in the next 30 days.
How severe is CVE-2026-33543?
CVE-2026-33543 is rated Critical with a CVSS score of 9.3. 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-2026-33543?
Yes. A fix has been recorded for CVE-2026-33543. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-33543 affect?
CVE-2026-33543 affects FOSSBilling <= 0.7.2. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-33543?
Upgrade to 0.8.0+.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can create an admin account and hijack an authenticated admin session via /api/guest/staff/create.
Patch immediately
- affected< 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.