Vulnerability in Penpot
CVE-2026-100868
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.
Published .
CVSS v3 metric
CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/penpot/penpot (product)
- github.com/penpot/penpot/blob/1d2c37e52c733f74017d90b0fd1ae2d074a5c33d/mcp/pack… (technical-description)
- github.com/penpot/penpot/commit/b5274a44766d095247037be18c1d1918ac67ddeb (patch)
- github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm (related, vendor-advisory)
- github.com/penpot/penpot/security/advisories/GHSA-ch2q-6x56-qg5r (vendor-advisory)
- www.vulncheck.com/advisories/penpot-before-2.18.0-unauthenticated-websocket-acc… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-100868?
- CVE-2026-100868 is a medium-severity vulnerability in Penpot, classified under CWE-1327. CVSS score: 6.3/10. Published 2026-09-27.
- How severe is CVE-2026-100868?
- Medium severity. CVSS v3 base score is 6.3 out of 10.