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Response snapshot Oct 26, 2026, 23:57 UTC

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VulnerabilityCVE-2026-114126

Storybook dev server vulnerable to code injection from the local network

**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.

At a glance

Exploited
Not known
Severity
8.7 High (CVSS 4.0)
Chance of exploitation
0.5% in the next 30 days
Sources
2 independent sources

What to do

GitHub lists first patched versions: storybook: 8.6.19; storybook: 9.1.21; storybook: 10.6.2; storybook: 11.0.0-alpha.6; @storybook/core: 8.6.19; @storybook/core-server: 8.6.19; @storybook/experimental-addon-test: 8.6.19; @storybook/addon-vitest: 9.1.21; @storybook/addon-vitest: 10.6.2; @storybook/addon-vitest: 11.0.0-alpha.6; @storybook/addon-mcp: 10.6.2; @storybook/addon-mcp: 11.0.0-alpha.6. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-px85-f4q5-jh77 (opens a new tab)

What happened

**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:

Continue reading

- 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 built version of Storybook on your machine

## Recommended actions

### Upgrade Storybook

Storybook has released patched versions of all affected major Storybook versions that fix all the vulnerabilities necessary for the worst-case scenario above to occur.

Upgrade to a patched version listed below before running `storybook dev` again. If you cannot upgrade immediately, do not run an affected Storybook dev server until you can apply the fix.

- 11.0.0-alpha.6 - 10.6.2 - 9.1.21 - 8.6.19

### Review potentially breaking changes

Due to the exceptional nature of the reported vulnerabilities, the Storybook team has decided to change the default behavior of Storybook, including versions 8 and 9, for several network-related features that are not essential to most Storybook users' workflow. If your team relies on the affected features, this document explains how to fall back to the previous behavior.

#### Storybook now only listens on `127.0.0.1` by default

By default, the Storybook dev server no longer binds to all network interfaces on your machine. It only binds to the loopback address `127.0.0.1`. You can still open it at `http://localhost:6006`. This prevents other devices on the same network from seeing your Storybook server.

To share a Storybook with others, consider publishing it to Chromatic (free). To share it 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.

To share a live Storybook running in dev mode, you can use the `--host` CLI option to bind to the LAN IP you want to share Storybook on, e.g. `storybook dev --host 192.168.0.110`. Host and origin validation stays enabled with this option. If you use `--host 0.0.0.0` instead, also set `core.allowedHosts` to the hostnames you will use. Without it, host and origin validation is disabled, and Storybook shows a warning and asks you to confirm before it starts.

Consider using a firewall to restrict incoming packets to known colleague IPs, and avoid using `--host` on an untrusted WiFi network.

#### The Vitest addon now disables `browser.api.allowWrite` and `browser.api.allowExec`

Storybook no longer allows code running in Vitest Browser mode to write to the developer’s machine or execute other processes. In the unlikely scenario that you rely on this capability in your tests, you can manually re-enable these APIs in your Vitest config.

#### The `saveStoryRequest` event validates input more strictly

Storybook strengthened input validation in `saveStoryRequest`, so addons and the Storybook UI can now only write serialized args and story titles. It is no longer possible to exploit input validation weaknesses to e.g. write `play` functions with a custom addon.

If you develop an addon that writes or edits files on users’ behalf, reach out to the Storybook team to get advice on security best practice.

## Disclosure timeline

On August 19th, the Storybook team received a responsible disclosure showing that the WebSocket token can be stolen by an attacker sharing a LAN with a Storybook dev server.

The disclosure identified several actions an attacker can do. An attacker can bypass input validation to write a payload in a story file.

They can then trigger a test run via the WebSocket. If the Vitest addon is installed, the payload can exploit a Vitest API to write other files, with more exploit logic to the user’s filesystem.

Depending on the exploit content, where the file is written, and what software the developer uses, that exploit could then be executed.

Affected package ranges reported by GitHub: storybook: >= 8.0.0, < 8.6.19 storybook: >= 9.0.0, < 9.1.21 storybook: >= 10.0.0, < 10.6.2 storybook: >= 11.0.0-alpha.0, < 11.0.0-alpha.6 @storybook/core: >= 8.0.0, < 8.6.19 @storybook/core-server: >= 8.0.0, < 8.6.19 @storybook/experimental-addon-test: >= 8.0.0, < 8.6.19 @storybook/addon-vitest: >= 9.0.0, < 9.1.21 @storybook/addon-vitest: >= 10.0.0, < 10.6.

2 @storybook/addon-vitest: >= 11.0.0-alpha.0, < 11.0.0-alpha.6 @storybook/addon-mcp: >= 10.6.0, < 10.6.2 @storybook/addon-mcp: >= 11.0.0-alpha.0, < 11.0.0-alpha.6

Scores and how they were measured

CVSS base severity

8.7

Version 4.0As of

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.5%

Scored Percentile 44.5%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-px85-f4q5-jh77 (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  4. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  5. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  6. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  7. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  8. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  9. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  10. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  11. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-px85-f4q5-jh77, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  12. Primary source

    NVD CVE-2026-114126 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  13. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  14. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-114126, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 22). Storybook dev server vulnerable to code injection from the local network (CVE-2026-114126). https://kevwire.com/record/CVE-2026-114126

MLA

"Storybook dev server vulnerable to code injection from the local network (CVE-2026-114126)." KEVWire, 22 Oct. 2026, kevwire.com/record/CVE-2026-114126.

Chicago

KEVWire. "Storybook dev server vulnerable to code injection from the local network (CVE-2026-114126)." Last modified October 22, 2026. https://kevwire.com/record/CVE-2026-114126.

Evidence summary (plain text)

Storybook dev server vulnerable to code injection from the local network (Oct 22, 2026).
**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.

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.
CVSS 8.7 (version 4.0; evidence as of Oct 22, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-114126).
EPSS 0.5% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-114126&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-px85-f4q5-jh77: https://github.com/advisories/GHSA-px85-f4q5-jh77
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo1MTozMFrOAAf0Mg%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0OToxMlrOAAf0LQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NzoxN1rOAAf0Kg%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NTozNlrOAAf0Jw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NTowNVrOAAf0JQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0Mzo0NVrOAAf0Iw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0MzozMVrOAAf0Ig%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODozNTowMVrOAAZRcw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODozMDoyN1rOAAY_5Q%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODoyOTowNVrOAAfz8g%3D%3D
NVD CVE-2026-114126: https://nvd.nist.gov/vuln/detail/CVE-2026-114126
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?pubStartDate=2026-10-12T13:35:55.142Z&pubEndDate=2026-10-26T13:35:55.142Z&resultsPerPage=500&startIndex=8000
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-114126&date=2026-10-26
Record ID: CVE-2026-114126.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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