CVE Intelligence
High File handling

CVE-2026-114126 — Storybook dev server: devices on the same network can obtain the WebSocket token and write code into story files

Storybook is a frontend workshop for building user interface components and pages in isolation. From 8.0.0 until 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6, the Storybook development server can expose its WebSocket authentication token to clients able to load its HTML pages over a local network. A LAN attacker can obtain the token and invoke WebSocket-backed file-writing or testing functionality. Weak story-write validation can allow code to be placed in story files. If the Storybook Vitest addon is installed with an old version of Vitest, the payload can use a Vitest API to write additional files or execute commands. Depending on the payload and local tooling, the attack can lead to code execution with the developer's privileges. This issue is fixed in 8.6.19, 9.1.21, 10.6.2, and 11.0.0-alpha.6.

Published Oct 21, 2026 · Updated Oct 22, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.5% (30-day exploitation probability)+7
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.53%
ahead of 44% of scored CVEs · Oct 25, 2026
Affects
Storybookjs
Storybook and 5 more
CVSS base
8.7
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Npm Storybook: fixed in version 8.6.19 — github.com (GitHub Security Advisories)
  • Npm Storybook: fixed in version 9.1.21 — github.com (GitHub Security Advisories)
  • Npm Storybook: fixed in version 10.6.2 — github.com (GitHub Security Advisories)
  • Npm Storybook: fixed in version 11.0.0-alpha.6 — github.com (GitHub Security Advisories)
  • Npm @storybook/core: fixed in version 8.6.19 — github.com (GitHub Security Advisories)
  • Npm @storybook/core-server: fixed in version 8.6.19 — github.com (GitHub Security Advisories)
  • Npm @storybook/experimental-addon-test: fixed in version 8.6.19 — github.com (GitHub Security Advisories)
  • Npm @storybook/addon-vitest: fixed in version 9.1.21 — github.com (GitHub Security Advisories)
  • Npm @storybook/addon-vitest: fixed in version 10.6.2 — github.com (GitHub Security Advisories)
  • Npm @storybook/addon-vitest: fixed in version 11.0.0-alpha.6 — github.com (GitHub Security Advisories)
  • Npm @storybook/addon-mcp: fixed in version 10.6.2 — github.com (GitHub Security Advisories)
  • Npm @storybook/addon-mcp: fixed in version 11.0.0-alpha.6 — github.com (GitHub Security Advisories)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Storybookjs Storybook, Npm @storybook/addon-mcp, Npm @storybook/addon-vitest…).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Search available logs for exploit probes matching the vulnerability class (file handling), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Storybookjs Storybook version >= 8.0.0, < 8.6.19version >= 9.0.0, < 9.1.21version >= 10.0.0, < 10.6.2version >= 11.0.0-alpha.0, < 11.0.0-alpha.6 Vulnerable CVE Program (cve.org) e CISA ADP
Npm @storybook/addon-mcp ≥ 10.6.0 and < 10.6.2≥ 11.0.0-alpha.0 and < 11.0.0-alpha.6 Vulnerable GitHub Security Advisories
Npm @storybook/addon-vitest ≥ 9.0.0 and < 9.1.21≥ 10.0.0 and < 10.6.2≥ 11.0.0-alpha.0 and < 11.0.0-alpha.6 Vulnerable GitHub Security Advisories
Npm @storybook/core ≥ 8.0.0 and < 8.6.19 Vulnerable GitHub Security Advisories
Npm @storybook/core-server ≥ 8.0.0 and < 8.6.19 Vulnerable GitHub Security Advisories
Npm @storybook/experimental-addon-test ≥ 8.0.0 and < 8.6.19 Vulnerable GitHub Security Advisories
Npm Storybook ≥ 8.0.0 and < 8.6.19≥ 9.0.0 and < 9.1.21≥ 10.0.0 and < 10.6.2≥ 11.0.0-alpha.0 and < 11.0.0-alpha.6 Vulnerable GitHub Security Advisories

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Adjacent
Attack complexity
Low
Attack requirements
None
Privileges required
None
User interaction
None
Scope
X
Confidentiality (vulnerable system)
High
Integrity (vulnerable system)
High
Availability (vulnerable system)
High
Confidentiality (subsequent)
Low
Integrity (subsequent)
Low
Availability (subsequent)
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.7 CVSS 4.0 High — — security-advisories@github.com via NIST National Vulnerability Database
8.7 CVSS 4.0 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
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 (score shown at the top: security-advisories@github.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-22 · Path Traversal

Other CVEs with this weakness →

EPSS over time FIRST

Oct 22, 2026 → Oct 25, 2026 · 4 reading(s) · max 0.53%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Monitor file creation in web directories and paths with traversal sequences (../).
file integrity (FIM)endpoint telemetry (EDR)

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 22, 2026 · GitHub Security Advisories
  • Affected products added · npm/storybook, npm/@storybook/core, npm/@storybook/core-server, npm/@storybook/experimental-addon-test, npm/@storybook/a
    Oct 22, 2026 · GitHub Security Advisories
  • Source status changed · Received → Awaiting Analysis
    Oct 22, 2026 · NIST National Vulnerability Database
  • Affected products added · storybookjs/storybook
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 21, 2026
  • CVSS changed · 8.7
    Oct 21, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 21, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 21, 2026 · Alertas do Telegram
  • CVE published
    Oct 21, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 21, 2026 – Oct 22, 2026
  • 1× Official description updated · Oct 21, 2026 – Oct 21, 2026

References

14 on the record

Elsewhere on this site

Storybookjs
every CVE for this vendor
File handling
same class
CWE-22
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-114125 Storybook: Missing origin validation in Storybook preview allows code injection from malicious websites 4d
  • CVE-2026-27148 Storybook Dev Server Vulnerable to WebSocket Hijacking Feb 25, 2026
  • CVE-2025-68429 Storybook manager bundle may expose environment variables during build Dec 17, 2025

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-114126 is "Storybook dev server: devices on the same network can obtain the WebSocket token and write code into story files", rated High. It affects Storybook (Storybookjs); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.7 describes technical severity. EPSS 0.53% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.