CVE-2026-4399
Prompt injection enables remote code execution in Millie chatbot.
Is CVE-2026-4399 being exploited?
Not confirmed. CVE-2026-4399 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 0.27% probability of exploitation in the next 30 days.
How severe is CVE-2026-4399?
CVE-2026-4399 is rated High with a CVSS score of 8.7. 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-2026-4399?
Not known from our data. No patch reference has been recorded for CVE-2026-4399, 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-2026-4399 affect?
CVE-2026-4399 affects 1millionbot Millie chatbot. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-4399?
Patch when released; enforce strict prompt controls and monitor API keys.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Attacker can bypass safeguards, trigger out-of-context actions, and misuse API keys to exploit the service.
Patch when possible
- affected3.6.0
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.