Storybook dev server vulnerable to code injection from the local network

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2026-114126: 0.53% estimated exploitation activity in the next 30 days; percentile 44.81 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary: The Storybook dev server exposes its WebSocket authentication token to any client that can load its HTML pages. Any host on a LAN can open a Storybook app by IP address, and therefore obtain the token. The WebSocket can be used to inject code into story files or to create new files. Under the right circumstances, an attacker can execute code on the machine of a developer connected on the same LAN. Who is impacted? You are impacted if you run a Storybook dev server whilst connected on an untrusted local network, or to a WiFi access point posing as a trusted network. The impact of this advisory is more important if you have the Vitest addon installed and are using an old version of Vitest. You are not impacted if: - You run a dev server in an environment that other devices on your network cannot reach (e.g. a container that does not publish the Storybook port, or publishes it only on 127.0.0.1) - You run a dev server whilst connected to a trusted local network - You serve a…

Published by the source

22 Oct 2026, 16:31 UTC

Last modified by the source

22 Oct 2026, 16:45 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 5 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-px85-f4q5-jh77

2. Revision 4 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-px85-f4q5-jh77

3. Revision 3 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

4. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-px85-f4q5-jh77

5. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-px85-f4q5-jh77

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# Patch Next advisory brief: CVE-2026-114126

Advisory: Storybook dev server vulnerable to code injection from the local network
IDs: CVE-2026-114126, GHSA-px85-f4q5-jh77
Record: https://patchnext.com/advisories/cve-2026-114126 (revision 5, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: storybook 11.0.0-alpha.6, 10.6.2, 9.1.21, 8.6.19; @storybook/core 8.6.19; @storybook/experimental-addon-test 8.6.19; @storybook/core-server 8.6.19; @storybook/addon-vitest 11.0.0-alpha.6, 10.6.2, 9.1.21; @storybook/addon-mcp 11.0.0-alpha.6, 10.6.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm storybook: affected >= 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; fixed in 11.0.0-alpha.6, 8.6.19, 10.6.2, 9.1.21
- npm @storybook/core: affected >= 8.0.0, < 8.6.19; fixed in 8.6.19
- npm @storybook/experimental-addon-test: affected >= 8.0.0, < 8.6.19; fixed in 8.6.19
- npm @storybook/core-server: affected >= 8.0.0, < 8.6.19; fixed in 8.6.19
- npm @storybook/addon-vitest: affected >= 9.0.0, < 9.1.21; >= 10.0.0, < 10.6.2; >= 11.0.0-alpha.0, < 11.0.0-alpha.6; fixed in 11.0.0-alpha.6, 10.6.2, 9.1.21
- npm @storybook/addon-mcp: affected >= 10.6.0, < 10.6.2; >= 11.0.0-alpha.0, < 11.0.0-alpha.6; fixed in 11.0.0-alpha.6, 10.6.2

## Suggested inspection (read-only)
- `npm ls storybook --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @storybook/core --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @storybook/experimental-addon-test --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @storybook/core-server --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @storybook/addon-vitest --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.
- `npm ls @storybook/addon-mcp --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on storybook, @storybook/core, @storybook/experimental-addon-test, @storybook/core-server, @storybook/addon-vitest, @storybook/addon-mcp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-px85-f4q5-jh77 (GitHub-reviewed advisory GHSA-px85-f4q5-jh77 lists affected ranges: npm storybook >=8.0.0 =9.0.0 =10.0.0 =11.0.0-alpha.0 =8.0.0 =8.0.0 =8.0.0 =9.0.0 =10.0.0 =11.0.0-alpha.0 =10.6.0 =11.0.0-alpha.0 <11.0.0-alpha.6)
- Verified: https://osv.dev/vulnerability/GHSA-px85-f4q5-jh77 (OSV record GHSA-px85-f4q5-jh77 lists affected ranges: npm storybook >=8.0.0 =9.0.0 =10.0.0 =11.0.0-alpha.0 =8.0.0 =8.0.0 =8.0.0 =9.0.0 =10.0.0 =11.0.0-alpha.0 <11.0.0-alpha.6 (fixed); npm @storybook/addon-mcp…)

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