CVE-2026-4399 Multiple vulnerabilities in 1millionbot Millie chatbot
Attackers can use prompt injection to bypass restrictions, execute unauthorized tasks, and access prohibited information via the Millie chatbot.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-4399?
CVE-2026-4399 is a high-severity code injection vulnerability in 1millionbot Millie chat, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-4399?
It affects 1 product.
Products include 1millionbot Millie Chatbot.
How do I fix CVE-2026-4399?
No fix has been published for CVE-2026-4399 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-4399 being exploited?
There is no known exploitation of CVE-2026-4399 in the wild and no public exploit code.
Other vulnerabilities in 1millionbot Millie chat
Sources
Also known as GHSA-7649-76jc-fc5r.