Researcher Broke Out of Microsoft Edge Using Only Design Mistakes

A security researcher has shown that Microsoft Edge could be broken open without the usual kind of coding bug. Orange Tsai of DEVCORE published his full method on October 28. The chain won $175,000 at the Pwn2Own Berlin hacking contest in May. Microsoft fixed the flaws the day after the contest, so an up-to-date Edge is not at risk.

What happened

Browsers keep web pages inside a sandbox, a wall that stops a page's code from touching the rest of your computer. Breaking out of it usually relies on memory corruption, a type of programming error. This chain used none. Tsai built it only from logic errors, meaning mistakes in how ordinary features were designed to work together. He says the whole exploit is under 100 lines of code.

How the chain worked

The first bug sits in an Edge feature for business sign-ins. Triggering it lets the browser start a new page load that Edge attaches to whichever tab is open. That lets an attacker run script on any website, even sites like google.com. Making it work without a click took four more weaknesses:

• Edge checked that a request came from a trusted Microsoft site, but opening it from a second window got past the check.
• A hardcoded list of allowed addresses let that second window slip past the popup blocker.
• Edge's auto-sign-in feature signed the victim in on its own after a visit to a Microsoft site.
• A misconfigured setting let any website read the victim's email address from assets.msn.com.

Escaping the sandbox came next. Tsai used Edge's reading mode, which Microsoft had left off a list of pages barred from running scripts. He then abused an internal function meant to zip up diagnostic logs, which let him write a file of his choosing anywhere on disk. By changing a settings file and restarting Edge, he made Windows hunt for a missing telnet program and run a planted copy instead.

Are you at risk

Almost certainly not. This was a contest exploit shown on stage. There is no evidence it was ever used against real users, and the public records list exploitation as none. Tsai notes that the browser restart step was a convenience for the contest and would not be needed in a real attack.

What to do

Microsoft shipped the fix on May 15 in Edge Stable version 148.0.3967.70. It carried three Edge fixes, tracked as CVE-2026-45492, CVE-2026-45494 and CVE-2026-45495. A browser on automatic updates received it months ago, so no extra action is needed. Anyone who turned updates off should update Edge.

Tsai says he built the chain by hand over about two months, without AI help. His work won the 2026 Pwnie Award for Epic Achievement. He calls the approach a new attack surface, not a one-off bug.