CVE-2026-4399 PUBLISHED

Multiple vulnerabilities in 1millionbot Millie chatbot

Assigner: INCIBE
Reserved: 18.03.2026 Published: 31.03.2026 Updated: 31.03.2026

Prompt injection vulnerability in 1millionbot Millie chatbot that occurs when a user manages to evade chat restrictions using Boolean prompt injection techniques (formulating a question in such a way that, upon receiving an affirmative response ('true'), the model executes the injected instruction), causing it to return prohibited information and information outside its intended context. Successful exploitation of this vulnerability could allow a malicious remote attacker to abuse the service for purposes other than those originally intended, or even execute out-of-context tasks using 1millionbot's resources and/or OpenAI's API key. This allows the attacker to evade the containment mechanisms implemented during LLM model training and obtain responses or chat behaviors that were originally restricted.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 8.7

Product Status

Vendor 1millionbot
Product Millie chat
Versions Default: unaffected
  • Version 3.6.0 is affected

Solutions

The vulnerabilities have been fixed by 1millionbot team in version 3.6.0.

Credits

  • David Utón Amaya (m3n0sd0n4ld) finder

References

Problem Types

  • CWE-1427 Improper neutralization of input used for LLM prompting CWE