---
id: CVE-2026-100868
title: >-
  Penpot before 2.18.0 binds the MCP server plugin WebSocket bridge to all
  network interfaces without authentication in single-user mode
summary: >-
  Penpot before 2.18.0 binds the MCP server plugin WebSocket bridge to all
  network interfaces without authentication in single-user mode. Unauthenticated
  attackers on adjacent networks can connect to the WebSocket port to
  impersonate the P…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-1327
vendor: penpot
product: penpot
affected:
  - penpot < 2.18.0
  - '@penpot/mcp <= 2.15.4'
published: '2026-09-27'
updated: '2026-09-27'
sourceUpdated: '2026-09-27T13:16:37.960'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100868'
references:
  - url: 'https://github.com/penpot/penpot'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d074a5c33d/mcp/packages/server/src/PluginBridge.ts#L52
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d1918ac67ddeb
    label: disclosure@vulncheck.com
  - url: 'https://github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm'
    label: disclosure@vulncheck.com
  - url: 'https://github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticated-websocket-access-via-mcp-bridge
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-27T13:53:26.573Z'
---

## Overview

Penpot before 2.18.0 binds the MCP server plugin WebSocket bridge to all network interfaces without authentication in single-user mode. Unauthenticated attackers on adjacent networks can connect to the WebSocket port to impersonate the Penpot browser plugin, intercept task payloads, and return forged results to the MCP client.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.