Apple has released patches for a bug that it claims “may have been exploited in an extremely sophisticated attack against specific targeted individuals,” according to a report. The zero-day bug was discovered in WebKit, the browser engine that powers Safari and other apps, allowing hackers to break out of WebKit’s protective sandbox with “maliciously crafted web content,” Apple stated. A sandbox is a crucial part of the operating system that, even if compromised, can prevent hackers from accessing data in other areas of the system.

The patch was made available on Tuesday for Macs, iPhones, iPads, Safari, and its Vision Pro headset.

Apple acknowledged that the attack targeted devices running software “before iOS 17.2.” However, no details about the hackers or their targets were disclosed. Despite a request for comment, Apple did not respond. In a separate incident in February, Apple also described an attack as “an extremely sophisticated attack against specific targeted individuals.” It is unclear whether the two incidents are related, as Apple had never used this terminology before the February patch.