Unintended Proxy or Intermediary ('Confused Deputy') Affecting storybook package, versions >=8.0.0 <8.6.19>=9.0.0 <9.1.21>=10.0.0 <10.6.2>=11.0.0-alpha.0 <11.0.0-alpha.6
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Unintended Proxy or Intermediary ('Confused Deputy') vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-JS-STORYBOOK-21689171
- published24 Oct 2026
- disclosed21 Oct 2026
- creditUnknown
Introduced: 21 Oct 2026
NewCVE-2026-114125 (opens in a new tab)How to fix?
Upgrade storybook to version 8.6.19, 9.1.21, 10.6.2, 11.0.0-alpha.6 or higher.
Overview
storybook is a frontend workshop for building UI components and pages in isolation.
Affected versions of this package are vulnerable to Unintended Proxy or Intermediary ('Confused Deputy') via the postMessage channel handler in code/core/src/channels/postmessage/index.ts, which does not validate the origin of incoming messages. An attacker who can cause a user to visit a malicious page can send arbitrary channel events to the Storybook preview iframe, enabling cross-origin control of the Storybook instance and potentially achieving full compromise of confidentiality, integrity, and availability of the preview context and the surrounding system.
Note: This is only exploitable when the Storybook dev server is accessible over the network and the user visits a page on a different origin that embeds or communicates with the Storybook iframe.