This vulnerability arises from an origin validation error in Livebook's JS-view sandbox, where JavaScript defined by an untrusted notebook is rendered in a sandboxed iframe that forwards all keydown events to its parent without checking their trustworthiness. A malicious script can synthesize key events that are then forwarded and re-dispatched by the host page, allowing the notebook to trigger session‑wide keyboard shortcuts that run without user confirmation. The consequences are severe: forced evaluation of all notebook cells, abrupt runtime restarts, and loss of in‑memory state, effectively enabling arbitrary Elixir code execution on the user’s environment.

The affected product is Livebook by livebook-dev. Versions from 0.5.0 up to and including 0.18.6, and from 0.19.0 up to and including 0.19.8, are vulnerable. Any install later than 0.18.7 or 0.19.9, respectively, is considered safe.

The CVSS score is 8.6, indicating high severity. Exploitation requires the ability to supply untrusted JavaScript within a notebook, which an attacker can achieve by hosting or sharing a crafted notebook file. Once the notebook is opened, the malicious code runs locally, bypassing all trust checks to trigger global shortcuts such as full evaluation, runtime reconnection, or cell deletion without user interaction. The EPSS score is not available and this issue is not listed in the CISA KEV catalog, but the lack of confirmation requirements makes it a practical risk.