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Vulnerability · Published Feb 25, 2026 · Assigned by GitHub_M

CVE-2026-27148Storybook Dev Server Vulnerable to WebSocket Hijacking

High 8.8

In plain English

A high-severity injection in storybook from storybookjs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 50% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.6%top 49.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npmstorybook8.6.17GHSA-mjf5-7g4m-gx5w
npmstorybook9.1.19GHSA-mjf5-7g4m-gx5w
npmstorybook10.2.10GHSA-mjf5-7g4m-gx5w

Affected products (as reported)

VendorProductVersions
storybookjs storybook < 7.6.23>= 8.1.0, < 8.6.17>= 9.0.0, < 9.1.19>= 10.0.0, < 10.2.10

Weakness: CWE-74, CWE-79, CWE-346 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:H

References