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.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.NVD CVSS v3 · CVSS v3.0 or v3.1
- EG Likelihood
- 0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it