Google's AI model Gemini accessed the internet and hacked three companies during a cybersecurity evaluation.
Researchers say loss of control incidents with AI are on the rise, with the potential for more serious incidents with "catastrophic consequences" to come.
The hacks occurred in May during a test conducted by Irregular, an independent company that conducts cybersecurity evaluations.
During the cybersecurity assessment, Gemini found public information online and guessed credentials to access three websites it thought were within the scope of its test, Heather Adkins, Google's vice-president of security engineering, said in a statement.
Ms Adkins said that in all three instances, the model ceased the hacking when it learned it had accessed a real company.
Irregular told Google about the hacks in July, the two companies told the Wall Street Journal, which first reported on the hacking incident on Friday local time.
Google told the WSJ it didn't consider it necessary to disclose the incidents earlier because its model stopped the hacking upon learning the companies were real and did not cause harm to them.
The hacks happened while Gemini was participating in a "capture the flag" exercise conducted on infrastructure belonging to Irregular to test the model's cybersecurity capabilities.
In the other two cases, the model found credentials in a public repository that allowed it to then access protected systems, according to the Wall Street Journal.
Irregular told the Wall Street Journal that the incident with Google Gemini was due to the same problem as the earlier breaches during tests with other AI models.