Storybook dev server CVE-2026-114125 (GHSA-f2ph-cmg5-wxc8): missing origin validation lets a malicious website change files in my project while 'storybook dev' is running. Which versions are fixed?

Applies to: storybook dev server 8.0-8.6.18, 9.0-9.1.20, 10.0-10.6.1, 11.0.0 alphas before alpha.6, and related @storybook packages

How it was checked: Compiled on 2026-11-01 from the Storybook security advisory, the v10.6.2 release and NVD; not reproduced by Exuvia.

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storybook
javascript
dev-server
cve-2026-114125
localhost
security

Fix

What it is: A critical Storybook advisory published 2026-10-21. While an affected Storybook development server is running and you browse the web, a malicious website could talk to the local dev server (it didn't validate request origins) and cause unauthorized changes to files in your project; under further conditions a changed file could then be run by a local tool with your privileges. Storybook said it was not aware of exploitation in the wild. The fix also changes some network-related defaults in Storybook 8 and 9, with feature flags to restore specific behaviours. Am I affected: - You run storybook dev (the dev server) on an affected version and open it in a browser: storybook 8.0.0-8.6.18, 9.0.0-9.1.20, 10.0.0-10.6.1, or 11.0.0 alphas before alpha.6. Related packages are covered too (@storybook/core and @storybook/core-server on 8.x, @storybook/addon-vitest, @storybook/experimental-addon-test, @storybook/addon-mcp). - Not affected: a static built Storybook, or a dev server never opened in a browser (headless automation, MCP clients). - Check: npx storybook --version, or npm ls storybook. Fix: 1. Upgrade before running the dev server again: 8.6.19, 9.1.21, 10.6.2 or 11.0.0-alpha.6 (npx storybook@latest upgrade, or bump storybook and all @storybook/* packages to matching versions). 2. Read the advisory's notes on changed defaults; only use the opt-out flags if your workflow truly needs them. 3. Until upgraded, don't run an affected dev server. Newer Chrome and Firefox may ask before a website can reach localhost; deny that permission to sites you don't trust. 4. If you ran an affected dev server while browsing untrusted sites, review git status/git diff for unexpected changes in the project and its config files. Verify: npx storybook --version shows a fixed release, and npm ls shows no older @storybook/* packages left. Sources: https://github.com/storybookjs/storybook/security/advisories/GHSA-f2ph-cmg5-wxc8 https://github.com/storybookjs/storybook/releases/tag/v10.6.2 https://nvd.nist.gov/vuln/detail/CVE-2026-114125

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