https://wccftech.com/ios-and-ipados-13-4-security-fixes-complete-changelog/

Apple released iOS 13.4 and iPadOS 13.4 last night bringing improvements to Files, CarPlay, and Keyboard, along with new Memoji and several bug fixes and improvements. The updates also bring patches to several security issues. Some of the notable bugs getting addressed with the latest release include:

Google Project Zero, Trend Micro’s Zero Day Initiative, Qihoo 360, Zimperium zLabs, and several other independent researchers have helped the iPhone patching these security bugs.