CVE-2026-27148
CriticalCVSS 9.6Exploitation Probability (EPSS)
Low risk42th percentile - higher than 42% of all known CVEs
Summary
A vulnerability in Storybook allows WebSocket hijacking in the dev server due to missing origin validation. Attackers can send malicious WebSocket messages, leading to persistent XSS or Remote Code Execution (RCE). Only the dev server is affected, not production builds.
Risk Assessment
The risk includes potential compromise of the development environment, enabling data theft, code modification, or further attacks on infrastructure. Publicly exposed instances are at higher risk.
Recommendation
Update Storybook to versions 7.6.23, 8.6.17, 9.1.19, or 10.2.10 immediately. For public instances, restrict access to the dev server and implement authentication.
Other vulnerabilities in Storybook
See all- CVE-2026-114126High
Storybook from 8.0.0 until 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6 allows the development server to expose its WebSocket authentication token to clients able to load its HTML pages over a local network. A LAN attacker can obtain the token and invoke WebSocket-backed file-writing or testing functionality. Weak story-write validation can allow code to be placed in story files, and with the Vitest addon, the payload can use a Vitest API to write files or execute commands, leading to code execution with developer privileges.
- CVE-2026-114125High
Storybook is a frontend workshop for building UI components and pages in isolation. From 8.0.0 until 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6, a malicious website can interact with the preview of a running Storybook development server due to insufficient iframe embedding and message-origin restrictions. A developer must visit the malicious website and interact with the injected interface.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS