https://www.theregister.co.uk/2019/08/26/apple_fixes_ios124_jailbreak/

Apple has issued an update to address a potentially serious security flaw it re-opened in the latest version of iOS.

Monday's iOS 12.4.1 update contains a single fix: a patch to address CVE-2019-8605. The use-after-free vulnerability would let an application gain the ability to execute arbitrary code with system privileges. Credit for discovering the flaw was given to Ned Williamson from Google's Project Zero team, who reported the flaw to Cupertino back in March.