DEVCORE Shows Sandboxed Safari 26.5 Code Execution at POC 2026

Researchers from DEVCORE demonstrated a WebKit exploit chain that achieved code execution inside Safari 26.5's web content process at POC 2026 in Seoul on November 12, according to dailysecu.com. The demonstration ran with the browser sandbox enabled and printed the contents of /etc/passwd.

The talk by Kuan-Ting Chen and Ting-Yu Chen was titled "Obvious Was Only the Beginning: A WebKit Exploit Chain for Pwn2Own". The researchers first found a use-after-free flaw in JavaScriptCore's WebAssembly memory growth handling, but it was already fixed in the shipping Safari build, so they moved on.

They then found a related memory bug in JavaScriptCore's DFG optimizing tier, where a mutable buffer address was treated as a constant. To bypass Apple Silicon's Pointer Authentication Code, they analyzed WebKit's JIT compilation and memory allocation.

The researchers said they used large language models to narrow the search scope and write code, while finding the pointer authentication bypass themselves. They noted Apple enabled a "JIT Cage" limiting the scope of JIT code execution in the macOS 27.3 beta, but said they had no time to verify its effect.

Limited to the web content process

The demo proved code execution inside Safari's web content process only, not full operating system access. The researchers said the Safari work was originally prepared for Pwn2Own Berlin 2026 but could not be demonstrated there.

POC 2026 runs November 12-13 at The Westin Seoul Parnas, with more than 400 security experts attending. The conference began in 2006 as Korea's first international hacking conference.