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.
References7
- github.com/penpot/penpot
- github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d07…
- github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d191…
- github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm
- github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r
- www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticat…
- github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r
Metrics
- CVSS 3.1
-
6.3
MEDIUM
Score source: CNA
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L - CVSS 4.0
-
5.3
MEDIUM
Score source: CNA
CVSS: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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 1% percentile: 45 · as of 9 November 2026
- CWE
- CWE-1327
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.