JS-view sandboxed output can synthesize keyboard events to trigger unconfirmed global shortcuts

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-66298
StatePUBLISHED
AssignerEEF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-05 20:17:12 UTC
Updated2026-08-05 20:17:12 UTC
DescriptionOrigin 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.

Risk And Classification

Primary CVSS: v4.0 8.6 HIGH from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-346 | CWE-346 CWE-346 Origin Validation Error

VersionSourceTypeScoreSeverityVector
4.06b3ad84c-e1a6-4bf7-a703-f496b71e49dbSecondary8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS8.6HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
Active
Confidentiality
High
Integrity
High
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Livebook-dev Livebook affected 0.5.0 0.18.7 semver Not specified
CNA Livebook-dev Livebook affected 0.19.0 0.19.9 semver Not specified
CNA Livebook-dev Livebook affected 0.5.0 0.18.7 other Not specified
CNA Livebook-dev Livebook affected 0.19.0 0.19.9 other Not specified
CNA Livebook-dev Livebook affected 0.5.0-cuda12 0.18.7-cuda12 other Not specified
CNA Livebook-dev Livebook affected 0.19.0-cuda12 0.19.9-cuda12 other Not specified
CNA Livebook-dev Livebook affected 844242ba80a928d0d675416d312a58003cb7771b * git Not specified

References

ReferenceSourceLinkTags
github.com/livebook-dev/livebook/commit/a552ce8f99ad348ea37061394dc950a0... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
github.com/livebook-dev/livebook/commit/5980e5c6b71036806b3bf54101eb1d6c... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
osv.dev/vulnerability/EEF-CVE-2026-66298 6b3ad84c-e1a6-4bf7-a703-f496b71e49db osv.dev
github.com/livebook-dev/livebook/security/advisories/GHSA-68c2-prqg-x62g 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
github.com/livebook-dev/livebook/commit/296318ffdfa6e5ed7b18ad8d5a5b2af9... 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com
cna.erlef.org/cves/CVE-2026-66298.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db cna.erlef.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Nguyễn Công Tú (en)

CNA: Jonatan Männchen / EEF (en)

CNA: Jonatan Kłosko (en)

CNA: José Valim (en)

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