Apple has released security updates that fix a WebKit zero-day vulnerability (CVE-2023-23529) that “may have been actively exploited.”
The bug has been fixed in iOS 16.3.1 and iPadOS 16.3.1, macOS Ventura 13.2.1, Safari 16.3.1, and possibly also in tvOS 16.3.2 and watchOS 9.3.1 – though release notes for the updates for those Internet of Things operating systems have been temporarily witheld.
CVE-2023-23529 is a type confusion issue in WebKit, the browser engine powering the Safari browser and other web browsers running on iOS and iPadOS.
The vulnerability is triggered by processing maliciously crafted web content, and may allow attackers to execute arbitrary code on a vulnerable device.
An anonymous researcher has been credited with reporting it, but since the update release notes acknowledge The Citizen Lab at The University of Toronto’s Munk School for their assistance, it’s possible that the vulnerability is being exploited to spy on users (the Lab often researches and reports on the use of mobile spyware around the world).
This is just speculation on our part, though, because as usual Apple did not share any details about the attacks.
Owners of iPhones, iPads and iPad minis are advised to check for available updates and upgrade their devices as soon as possible. Users of older devices (e.g., iPhone 7 and older) will have to wait for the patch to be backported to older iOS and iPadOS branches.
Other fixed vulnerabilities
Users running macOS Ventura also get a patch for CVE-2023-23529 with the OS security update, while those who still use macOS Big Sur and macOS Monterey can close the hole by updating Safari to version 16.3.1.
The iOS and iPadOS update also contains a fix for CVE-2023-23514, a use after free issue in the kernel, which could allow a malicious app to execute arbitrary code with kernel privileges.
The macOS update patches it, as well, along with a privacy issue in the Shortcuts component.