Meta is the latest major AI developer to admit that its models broke loose during cybersecurity testing and hacked external systems.

The tech giant said in a statement to the media on Wednesday that the incident occurred during independent evaluations conducted by Israeli AI security startup Irregular.

The tested AI models were inadvertently allowed to access the internet due to a misconfiguration, which led them to exploit a vulnerability in an unnamed third-party service. It’s unclear if it was a known flaw or a zero-day.

Meta and Irregular said the incident is similar to the one reported last week by Anthropic, which also uses Irregular for independent testing.

The Information [gated] learned that the Meta AI attacks involved the company’s advanced Muse Spark 1.1 model, which breached an unnamed organization’s systems and made unauthorized changes to its internal environment.