VSCode github.dev Token Stealing Vulnerability

A security researcher has disclosed a critical vulnerability in the web-based version of VSCode (github.dev) that allows for one-click exfiltration of GitHub OAuth tokens. By redirecting a victim to a specially crafted repository containing a Jupyter notebook, an attacker can exploit a flaw in how VSCode bubbles up keyboard events from isolated webviews to the main application window.

The attack chain involves simulating keyboard shortcuts to bypass security prompts and install a 'local workspace extension' that executes arbitrary code. Because the OAuth token provided to github.dev has broad read/write access to all of a user's repositories, successful exploitation grants the attacker full access to the victim's private source code and infrastructure.

While a stopgap fix was applied on June 3, 2026, users who have previously authorized github.dev remain at risk if they do not clear their browser's local site data. The vulnerability highlights a significant risk in the 'github.dev' ecosystem where the security boundary between untrusted webview content and the core editor can be subverted through simulated user interaction.