<aside>

If you have a deployment of marimo exposed to the public, please upgrade to

marimo>=0.23.0

</aside>

Summary

The /terminal/ws endpoint is accessible without authentication on default marimo installations. This allows for unauthenticated users to remote execute code via this endpoint

Advisory: https://github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xc

CWE-306: Missing Authentication for Critical Function

CVE: CVE-2026-39987

What versions are affected

marimo <= 0.22.5

Who is affected

• If you have deployed marimo as an editable notebook (not an application) to the public internet and only using marimo’s built-in authentication.
• If you expose marimo to your shared network using --host 0.0.0.0 and while in edit mode (not an application).

Likely not affected

You are not affected if any of these are true.

• If you have your own authentication proxy on top of editable marimo notebooks.
• If you are not exposing marimo to the public internet
• If you are running marimo as an application (in run mode)
• WebAssembly (WASM) notebooks are not affected