IOS

This post documents the complete exploitation of a type declaration error in WebKit’s JavaScriptCore DFG compiler — from NodeResultInt32 (should have been NodeResultJS) in the DFGNodeType.h macro table, through GC write barrier bypass triggering Use-After-Free, escalating step by step to stable arbitrary memory read/write (AAR/AAW) on a stock, non-jailbroken iPhone (iOS 26.1). End-to-end success rate is approximately 80%. Field Value Vulnerability location Source/JavaScriptCore/dfg/DFGNodeType.h — MapIterationEntryKey node Bugzilla 304950 rdar 167200795 Fix commit 3f6f7836068 (cherry-pick 47b55468bf82) Affected versions Safari ≤ 26.2 (WebKit 7623.1.14.11.9) Fixed in Safari 26.3 (20623.2.7) — Security advisory Target devices iPhone / vphone (iOS 26.1) and macOS 26.2 Exploit success rate ~80% (failures typically manifest as page reloads; unresponsive crashes are rare) Vulnerability Overview During JavaScript-to-machine-code compilation, JavaScriptCore (JSC) employs an intermediate-tier compiler called DFG (Data Flow Graph). DFG attaches an output type declaration (NodeResult) to each IR node, telling subsequent optimization passes what type of value the node produces. ...

Have you ever wanted to peek inside an app on your iPhone or iPad to see exactly what data it’s processing, especially to understand what information it’s sending or receiving? Today, I’ll introduce you to a simple yet powerful method using Frida, which enables you to dynamically detect the parameters of a special piece of code called a “block” within iOS applications. First: What Exactly is a Block? In iOS programming, a block is a small, self-contained piece of code that you can pass around your app to be executed later. Imagine it as giving your phone number (the block) to a friend who can then call you when something important happens. ...