Storybook dev server leaks its WebSocket token to the local network, leading to code injection
- Product
- Storybook
- CVE
- CVE-2026-114126
- Affected
- npm/storybook 8.0.0 to 8.6.19, 9.0.0 to 9.1.21, 10.0.0 to 10.6.2, 11.0.0-alpha.0 to 11.0.0-alpha.6
- Fixed in
- 8.6.19
Last verified against sources: October 26, 2026
Am I affected?
Storybook: affected npm/storybook 8.0.0 to 8.6.19, 9.0.0 to 9.1.21, 10.0.0 to 10.6.2, 11.0.0-alpha.0 to 11.0.0-alpha.6. Fixed in 8.6.19.
- Check your version: run
npm ls storybook. Versions >= 8.0.0, < 8.6.19 of storybook are affected. [1] - Check your version: run
npm ls @storybook/core. Versions >= 8.0.0, < 8.6.19 of @storybook/core are affected. [1] - Check your version: run
npm ls @storybook/core-server. Versions >= 8.0.0, < 8.6.19 of @storybook/core-server are affected. [1]
What to do now
- Upgrade to the fixed version: run
npm install storybook@8.6.19(first patched version 8.6.19). [1] - Upgrade to the fixed version: run
npm install @storybook/core@8.6.19(first patched version 8.6.19). [1] - Upgrade to the fixed version: run
npm install @storybook/core-server@8.6.19(first patched version 8.6.19). [1] - Upgrade to a patched version before running storybook dev again: 8.6.19, 9.1.21, 10.6.2 or 11.0.0-alpha.6. [1]
- If you cannot upgrade right away, do not run an affected Storybook dev server until you can apply the fix. [1]
- To share a Storybook on a LAN without exposing the dev server, build a static Storybook with storybook build and serve the output folder with any static file server. [1]
- Avoid using the --host option on an untrusted WiFi network. [1]
General practice, not from the source: if the affected software could read tokens or credentials, rotate them after upgrading; pin versions and review changes before updating tools your agents run.
What happened
Impact
- An attacker on the same local network can use the WebSocket to inject code into story files or create new files. [1]
- Under the right circumstances, an attacker can run code on the machine of a developer on the same network. [1]
- If the Vitest addon is installed and an old Vitest version is used, the attack can also write other files to the developer's filesystem. [1]
What was done
- Storybook released patched versions of all affected major Storybook versions: 11.0.0-alpha.6, 10.6.2, 9.1.21 and 8.6.19. [1]
- The dev server now listens only on the loopback address 127.0.0.1 by default. [1]
- The Vitest addon now disables browser.api.allowWrite and browser.api.allowExec. [1]
- The saveStoryRequest event now validates input more strictly. [1]
Sources
- GHSA-px85-f4q5-jh77 — GitHub Advisory Database
Every statement above was checked against these sources before publishing. Spotted an error? Tell us and we will correct it with a dated note.
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[CVE-2026-114126] Storybook dev server leaks its WebSocket token to the local network, leading to code injection
Product: Storybook | Affected: npm/storybook 8.0.0 to 8.6.19, 9.0.0 to 9.1.21, 10.0.0 to 10.6.2, 11.0.0-alpha.0 to 11.0.0-alpha.6 | Fixed in: 8.6.19
Summary: The Storybook dev server gives its WebSocket login token to any client that can load its web pages.
Source & remediation on AgentArmorHQ: https://agentarmorhq.com/incidents/2026/10/cve-2026-114126-storybookCorrections
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