CVE-2026-3431
Auth bypass in SimStudio (<0.5.74) enables connecting to any reachable MongoDB and CRUD.
Is CVE-2026-3431 being exploited?
Not confirmed. CVE-2026-3431 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 0.35% probability of exploitation in the next 30 days.
How severe is CVE-2026-3431?
CVE-2026-3431 is rated Critical with a CVSS score of 9.8. 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-2026-3431?
Not known from our data. No patch reference has been recorded for CVE-2026-3431, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-3431 affect?
CVE-2026-3431 affects SimStudio < 0.5.74, MongoDB instances reachable via SimStudio endpoints. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-3431?
Upgrade to 0.5.74+ when available; restrict endpoint exposure.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated remote access to MongoDB via SimStudio endpoints; read, modify, and delete data.
Immediate action required
- affected< 0.5.74
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.