livebook: Origin Validation Error
CVE-2026-66298 is a high-severity origin validation error vulnerability in livebook from Livebook-dev, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. The record lists versions 0.18.7, 0.19.9, 0.18.7-cuda12 as the first without the flaw, so updating livebook to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.27% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update livebook to 0.18.7 or 0.19.9 or 0.18.7-cuda12 or 0.19.9-cuda12, whichever matches your release line, or a later version.
- Read the advisory on cna.erlef.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Livebook-dev | livebook | 0.5.0 up to, but not including, 0.18.7; 0.19.0 up to, but not including, 0.19.9; 0.5.0-cuda12 up to, but not including, 0.18.7-cuda12; 0.19.0-cuda12 up to, but not including, 0.19.9-cuda12; 844242ba80a928d0d675416d312a58003cb7771b and later | 0.18.7, 0.19.9, 0.18.7-cuda12, 0.19.9-cuda12 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.6 | High | CNA |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
Origin Validation Error vulnerability in livebook-dev livebook allows untrusted notebook output JavaScript to trigger session-wide keyboard shortcuts, including forced evaluation of all cells and runtime restart. Livebook's JS-view feature renders notebook-defined JavaScript inside a sandboxed, cross-origin iframe specifically because that JavaScript is untrusted. The trusted iframe shell in iframe/priv/static/iframe/v5.html forwards every keydown event fired in its own window to the parent page without consulting Event.isTrusted, so an event synthesized by the untrusted script through window.dispatchEvent is forwarded exactly as a genuine keystroke would be. The parent-side relay in assets/js/hooks/js_view.js reconstructs and re-dispatches it on the live page with no further validation, and because assets/js/hooks/session.js registers the global shortcut handler on the document in the capture phase, that handler acts on the replicated event regardless of how it was produced. Sandboxed output JavaScript can therefore drive Livebook's session-wide keyboard shortcuts. Two of them reach LivebookWeb.SessionLive and execute immediately with no confirmation: the shortcut for queueing full evaluation runs every cell in the notebook, and the shortcut for reconnecting the runtime disconnects and reconnects it, discarding in-memory state. A third shortcut deletes the focused cell behind a confirmation dialog that the user can permanently dismiss, after which it too executes silently. Forced full evaluation is the significant consequence, because it causes the notebook's own Elixir code to run without the user choosing to evaluate anything. A user who merely opens a notebook obtained from a third party, or reached from published documentation, can have its code executed on their runtime. Livebook also mirrors cell outputs to every connected client, so a malicious output triggers in a collaborator's browser as soon as it renders. This issue affects livebook: from 0.5.0 before 0.18.7 and from 0.19.0 before 0.19.9.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/livebook-dev/livebook/commit/296318ffdfa6e5ed7b18ad8d5a5b2af90f3cd728
- github.com/livebook-dev/livebook/commit/5980e5c6b71036806b3bf54101eb1d6c0f50f19c
- github.com/livebook-dev/livebook/commit/844242ba80a928d0d675416d312a58003cb7771b
- github.com/livebook-dev/livebook/commit/a552ce8f99ad348ea37061394dc950a0cebdb33e
Third-party and government advisories
- osv.dev/vulnerability/EEF-CVE-2026-66298Third Party Advisory
Other vulnerabilities in livebook
- 8.8 High severity
- 8.1 High severity
- 8.0 High severity
- 9.8 Critical severity
Recent Origin Validation Error vulnerabilities
- 9.8 Critical severity
- 9.4 Critical severity
- 8.8 High severity
- 7.5 High severity
- 7.8 High severity
- 8.8 High severity
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