High

Kottster app reinitialization can be re-triggered allowing command injection in development mode

  • Disclosed: 23.10.2025
  • Updated: 11.10.2026 10:22

Impact

Development mode only. Kottster contains a pre-authentication remote code execution (RCE) vulnerability when running in development mode.

The vulnerability combines two issues:

  1. The initApp action can be called repeatedly without checking if the app is already initialized, allowing attackers to create a new root admin account and obtain a JWT token
  2. The installPackagesForDataSource action uses unescaped command arguments, enabling command injection

An attacker with access to a locally running development instance can chain these vulnerabilities to:

  • Reinitialize the application and receive a JWT token for a new root account
  • Use this token to authenticate
  • Execute arbitrary system commands through installPackagesForDataSource

Production deployments were never affected.

Patches

Fixed in v3.3.2.

Specifically, @kottster/server v3.3.2 and @kottster/cli v3.3.2 address this vulnerability.

We recommend developers using earlier versions of @kottster/server and @kottster/cli update all the core packages to latest release:

bash
npm install @kottster/common@latest @kottster/cli@latest @kottster/server@latest @kottster/react@latest

Workarounds

  • Do not expose development servers to public networks or untrusted users
  • Use production mode for any deployment accessible from outside trusted environments

Credit

We sincerely thank Jeongwon Jo (@P0cas) from RedAlert for discovering and responsibly disclosing this vulnerability.

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package @kottster/server >= 3.2.0, < 3.3.2 3.3.2

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U
Weakness (CWE)
CWE-284, CWE-78
Platform
npm
Package
@kottster/server
Disclosed
23.10.2025
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-j3w7-9qc3-g96p - CC BY 4.0

Vulnerability history: @kottster/server

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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