CVE-2026-114126

**Summary:** The Storybook dev server exposes its WebSocket authentication token to any client that can load its HTML pages. Any host on a LAN can open a Storybook app by IP address, and therefore obtain the token. The WebSocket can be used to inject code into story files or to create new files. Under the right circumstances, an attacker can execute code on the machine of a developer connected on the same LAN. ## Who is impacted? You are impacted if you run a Storybook dev server whilst connected on an untrusted local network, or to a WiFi access point posing as a trusted network. The impact of this advisory is more important if you have the Vitest addon installed and are using an old version of Vitest. You are not impacted if: - You run a dev server in an environment that other devices on your network cannot reach (e.g. a container that does not publish the Storybook port, or publishes it only on `127.0.0.1`) - You run a dev server whilst connected to a trusted local network - You serve a built version of Storybook on your machine ## Recommended actions ### Upgrade Storybook Storybook has released patched versions of all affected major Storybook versions that fix all the vulnerabilities necessary for the worst-case scenario above to occur. Upgrade to a patched version listed below before running `storybook dev` again. If you cannot upgrade immediately, do not run an affected Storybook dev server until you can apply the fix. - 11.0.0-alpha.6 - 10.6.2 - 9.1.21 - 8.6.19 ### Review potentially breaking changes Due to the exceptional nature of the reported vulnerabilities, the Storybook team has decided to change the default behavior of Storybook, including versions 8 and 9, for several network-related features that are not essential to most Storybook users' workflow. If your team relies on the affected features, this document explains how to fall back to the previous behavior. #### Storybook now only listens on `127.0.0.1` by default By default, the Story