CVE-2026-100868
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.
Does this matter?
Lower severity and a low EPSS score (0.53%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 4.0
- 5.3 MEDIUMCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.53% probability · 45th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-1327
- Source
- disclosure@vulncheck.com
EPSS moved from 0.3% on 28 September 2026 to 0.5% on 26 October 2026.
References
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.