The FBI told the company that the disclosure resulted from the so-called Vulnerability Equities Process for deciding what to do with information about security holes, Apple said.

The process, which has been in place in its current form since 2014, is meant to balance law enforcement and U.S. intelligence desires to hack into devices with the need to warn manufacturers so that they can patch holes before criminals and other hackers take advantage of them.

The vulnerability that was disclosed to Apple involved older versions of the iPhone and the Mac, Apple said.

The issue of how U.S. government agencies decide to share information about vulnerabilities in computer and telecom products has received renewed scrutiny since the FBI announced last month that it had found a way to break into the iPhone of one of the shooters in December's massacre in San Bernardino, California.