About the security content of iOS 11.3.1

This document describes the security content of iOS 11.3.1.

About Apple security updates

For our customers' protection, Apple doesn't disclose, discuss, or confirm security issues until an investigation has occurred and patches or releases are available. Recent releases are listed on the Apple security updates page.

For more information about security, see the Apple Product Security page. You can encrypt communications with Apple using the Apple Product Security PGP Key.

Apple security documents reference vulnerabilities by CVE-ID when possible.

iOS 11.3.1

Crash Reporter

Available for: iPhone 5s and later, iPad Air and later, and iPod touch 6th generation

Impact: An application may be able to gain elevated privileges

Description: A memory corruption issue was addressed with improved error handling.

CVE-2018-4206: Ian Beer of Google Project Zero

LinkPresentation

Available for: iPhone 5s and later, iPad Air and later, and iPod touch 6th generation

Impact: Processing a maliciously crafted text message may lead to UI spoofing

Description: A spoofing issue existed in the handling of URLs. This issue was addressed with improved input validation.

CVE-2018-4187: Zhiyang Zeng (@Wester) of Tencent Security Platform Department, Roman Mueller (@faker_)

WebKit

Available for: iPhone 5s and later, iPad Air and later, and iPod touch 6th generation

Impact: Processing maliciously crafted web content may lead to arbitrary code execution

Description: A memory corruption issue was addressed with improved state management.

CVE-2018-4200: Ivan Fratric of Google Project Zero

WebKit

Available for: iPhone 5s and later, iPad Air and later, and iPod touch 6th generation

Impact: Processing maliciously crafted web content may lead to arbitrary code execution

Description: A memory corruption issue was addressed with improved memory handling.

CVE-2018-4204: Richard Zhu (fluorescence) working with Trend Micro's Zero Day Initiative, found by OSS-Fuzz