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.
Fix
Nothing published yet: no patch, vendor advisory or mitigation reference on NVD, no vendor advisory in the News for this CVE, not in CISA's KEV, no fixed package version. BaselineWatch does not guess at one.
Change history 1
- First seenCVSS 5.3NVD modified 2026-10-08 16:17
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 7
- https://github.com/penpot/penpot
- https://github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d074a5c33d/mcp/packages/server/src/PluginBridge.ts#L52
- https://github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d1918ac67ddeb
- https://github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm
- https://github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r
- https://www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticated-websocket-access-via-mcp-bridge
- https://github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r