Skip to content
Fencer Vulns
high 8.8

CVE-2026-27148 json

Storybook Dev Server Vulnerable to WebSocket Hijacking

published 2026-02-25 8 mo ago modified 2026-07-15 3 mo ago also GHSA-mjf5-7g4m-gx5w , EUVD-2026-8750

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

Storybook is a frontend workshop for building user interface components and pages in isolation. Prior to versions 7.6.23, 8.6.17, 9.1.19, and 10.2.10, the WebSocket functionality in Storybook's dev server, used to create and update stories, is vulnerable to WebSocket hijacking. This vulnerability only affects the Storybook dev server; production builds are not impacted. Exploitation requires a developer to visit a malicious website while their local Storybook dev server is running. Because the WebSocket connection does not validate the origin of incoming connections, a malicious site can silently send WebSocket messages to the local instance without any further user interaction. If the Storybook dev server is intentionally exposed publicly (e.g. for design reviews or stakeholder demos) the risk is higher, as no malicious site visit is required. Any unauthenticated attacker can send WebSocket messages to it directly. The vulnerability affects the WebSocket message handlers for creating and saving stories. Both are vulnerable to injection via unsanitized input in the componentFilePath field, which can be exploited to achieve persistent XSS or Remote Code Execution (RCE). Versions 7.6.23, 8.6.17, 9.1.19, and 10.2.10 contain a fix for the issue.

Patch / fix

  • npm storybook 8.6.17, 9.1.19, 10.2.10
  • storybook storybook 7.6.23, 8.6.17, 9.1.19, 10.2.10

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-27148 updated cvss 8.8

storybook: Storybook: Remote Code Execution via WebSocket Hijacking

  • Red Hat streams for Apache Kafka 3 com.github.streamshub-console
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 9 grafana, grafana-selinux Red Hat Enterprise Linux 10 grafana Red Hat streams for Apache Kafka 2 com.github.streamshub-console
    not affected: vulnerable code not in execute path

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
8 mo ago

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 8.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CISA ADP 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:H
CNA 4.0 8.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
NVD 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:H

Affected packages

ecosystem package affected fixed in
npm storybook
>=8.1.0, <8.6.17
>=8.7.0-alpha.0, <9.1.19
>=10.0.0-beta.0, <10.2.10
8.6.17
9.1.19
10.2.10

Affected products

  • storybookjs storybook
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat streams for Apache Kafka 2
  • Red Hat streams for Apache Kafka 3

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
  • CWE-79 Improper Neutralization of Input During Web Page Generation
  • CWE-346 Origin Validation Error
  • CWE-1385 Missing Origin Validation in WebSockets

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.