Componentpedia / Listings / storybook / 8.4.7

Storybook is a frontend workshop for building user interface components and pages in isolation. Prior to versions 7.6.23, 8.6.17, 9.1.19, and 10.2.10, the WebSocket functionality in Storybook's dev server, used to create and update stories, is vulnerable to WebSocket hijacking. This vulnerability only affects the Storybook dev server; production builds are not impacted. Exploitation requires a developer to visit a malicious website while their local Storybook dev server is running. Because the WebSocket connection does not validate the origin of incoming connections, a malicious site can silently send WebSocket messages to the local instance without any further user interaction. If the Storybook dev server is intentionally exposed publicly (e.g. for design reviews or stakeholder demos) the risk is higher, as no malicious site visit is required. Any unauthenticated attacker can send WebSocket messages to it directly. The vulnerability affects the WebSocket message handlers for creating and saving stories. Both are vulnerable to injection via unsanitized input in the componentFilePath field, which can be exploited to achieve persistent XSS or Remote Code Execution (RCE). Versions 7.6.23, 8.6.17, 9.1.19, and 10.2.10 contain a fix for the issue.

Storybook is a frontend workshop for building user interface components and pages in isolation. A vulnerability present starting in versions 7.0.0 and prior to versions 7.6.21, 8.6.15, 9.1.17, and 10.1.10 relates to Storybook’s handling of environment variables defined in a .env file, which could, in specific circumstances, lead to those variables being unexpectedly bundled into the artifacts created by the storybook build command. When a built Storybook is published to the web, the bundle’s source is viewable, thus potentially exposing those variables to anyone with access. For a project to potentially be vulnerable to this issue, it must build the Storybook (i.e. run storybook build directly or indirectly) in a directory that contains a .env file (including variants like .env.local) and publish the built Storybook to the web. Storybooks built without a .env file at build time are not affected, including common CI-based builds where secrets are provided via platform environment variables rather than .env files. Storybook runtime environments (i.e. storybook dev) are not affected. Deployed applications that share a repo with your Storybook are not affected. Users should upgrade their Storybook—on both their local machines and CI environment—to version .6.21, 8.6.15, 9.1.17, or 10.1.10 as soon as possible. Maintainers additionally recommend that users audit for any sensitive secrets provided via .env files and rotate those keys. Some projects may have been relying on the undocumented behavior at the heart of this issue and will need to change how they reference environment variables after this update. If a project can no longer read necessary environmental variable values, either prefix the variables with STORYBOOK_ or use the env property in Storybook’s configuration to manually specify values. In either case, do not include sensitive secrets as they will be included in the built bundle.

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.

Summary: A malicious website may be able to cause unauthorized file changes in a developer’s project while an affected Storybook development server is running. Under additional conditions, a changed file could be executed by a local runtime with the developer’s privileges. We are not aware of exploitation in the wild.