CVE-2026-100868

MEDIUM 6.3

Penpot before 2.18.0 Unauthenticated WebSocket Access via MCP Bridge

CVSS Score

6.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-1327
Vendor	penpot
Product	penpot
Published	Sep 27, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Affected Versions

penpot / penpot

0 < 2.18.0

penpot / @penpot/mcp

0 ≤ 2.15.4

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r github.com: https://github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d1918ac67ddeb github.com: https://github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d074a5c33d/mcp/packages/server/src/PluginBridge.ts#L52 github.com: https://github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm github.com: https://github.com/penpot/penpot vulncheck.com: https://www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticated-websocket-access-via-mcp-bridge

Credits

George Chen