ChatGPT Agent Builder flaw let hackers deploy rogue AI agents with one click

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Zenity Labs found AgentForger, a flaw in OpenAI’s ChatGPT Agent Builder

Malicious links could instantly deploy rogue agents that exfiltrate sensitive data without user prompts

OpenAI patched the issue by removing the risky URL parameter; no abuse detected

AI agents are handy for answering customer emails, or tracking reports for newly released security vulnerabilities. But what if they go rogue and turn on the very enterprise they’re supposed to support?

Security researchers from Zenity Labs have found a way for cybercriminals to trick people into deploying such agents into their own tech stack. Since all it takes is a single click, the disruptive potential of these attacks is arguably significantly bigger than anything else a phishing attack could do.

The flaw was discovered in OpenAI’s ChatGPT Agent Builder, a feature that lets users create custom AI agents. The researchers dubbed it “AgentForger", explaining that the issue stems from an overly permissive parameter in the tool, which allowed anyone to create ChatGPT links that include virtually any instructions.

Agent trust failure

As soon as the victim clicks on the link, they send the instructions to Agent Builder which acts on them immediately - without prompting or otherwise notifying the victim.

In theory, a single phishing email could trick a person into deploying a malicious agent that exfiltrates sensitive data or does anything else that company’s AI agents are permitted to do. To make matters worse, the AI agent would persist on the infrastructure indefinitely, doing the attackers’ bidding until caught.

“This is an agent trust failure, and existing security controls were never built to see it,” commented Michael Bargury, co-founder and CTO of Zenity.

The researchers disclosed their findings with OpenAI in early June 2026, and the company came back with a fix a few days later.

The bug was solved by removing the URL parameter that originally enabled the attack, it was explained. There is no evidence that it was previously discovered, or abused, by malicious actors.