CVE-2026-45805: PenPot MCP REPL server binds to 0.0.0.0 with unauthenticated /execute endpoint — RCE

May 19, 2026

The MCP module’s ReplServer binds to all interfaces (0.0.0.0:4403) and exposes a /execute endpoint that runs arbitrary code with zero authentication. Anyone on the network can POST JavaScript and it runs on the server. The main PenpotMcpServer was partially fixed for a similar binding issue (#8683), but ReplServer.ts was missed.

References

github.com/advisories/GHSA-22qr-rp27-j9wm
github.com/penpot/penpot/security/advisories/GHSA-22qr-rp27-j9wm
nvd.nist.gov/vuln/detail/CVE-2026-45805

Code Behaviors & Features

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