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NVD / CVE Program· CNA EEF

CVE-2026-66298: JS-view sandboxed output can synthesize keyboard events to trigger unconfirmed global shortcuts

HighCVSS 8.6 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 34/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.27% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: livebook-dev livebook 0.18.7, 0.18.7-cuda12, 0.19.9.

Low priority for now. Upgrade to livebook-dev livebook 0.18.7, 0.18.7-cuda12, 0.19.9 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Aug 5, 2026
Updated
Nov 10, 2026
EPSS
0.2% · 19th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
8.6
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-66298

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
livebooklivebook

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • livebook-dev livebook

    • 0.5.0 and later · before 0.18.7affected · semver
    • 0.19.0 and later · before 0.19.9affected · semver
    • 0.5.0 and later · before 0.18.7affected · other
    • 0.5.0-cuda12 and later · before 0.18.7-cuda12affected · other
    • 0.19.0 and later · before 0.19.9affected · other
    • 0.19.0-cuda12 and later · before 0.19.9-cuda12affected · other
    • 844242ba80a928d0d675416d312a58003cb7771b and lateraffected · gitfixed in 296318ffdfa6e5ed7b18ad8d5a5b2af90f3cd728, a552ce8f99ad348ea37061394dc950a0cebdb33e, 5980e5c6b71036806b3bf54101eb1d6c0f50f19c

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • livebook livebook0.5.0 and later · before 0.18.7
  • livebook livebook0.19.0 and later · before 0.19.9

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Hexlivebookfrom 0.19.0 · before 0.19.90.19.9
Hexlivebookfrom 0.5.0 · before 0.18.70.18.7

Same product

livebook: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-35174Livebook Desktop's protocol handler can be exploited to execute arbitrary command on Windows
    39Monitor
  • CVE-2026-68746Livebook Teams identity check fails open when the deployment group is unresolvable, allowing unauthenticated access
    30Monitor
  • CVE-2026-66881Path traversal in imported file_entries name allows arbitrary file write via URL-type entry download
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-66297Aug 5, 2026 · Unescaped deployment environment variables in generated setup commands
    21Monitor
  • Later →CVE-2026-66885Aug 5, 2026 · Livebook Teams identity callback lacks state binding, allowing login CSRF
    27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
livebook-dev livebook0.18.7Vendor (CNA)
livebook-dev livebook0.18.7-cuda12Vendor (CNA)
livebook-dev livebook0.19.9Vendor (CNA)
livebook-dev livebook0.19.9-cuda12Vendor (CNA)
livebook-dev livebook296318ffdfa6e5ed7b18ad8d5a5b2af90f3cd728Vendor (CNA)
livebook-dev livebook5980e5c6b71036806b3bf54101eb1d6c0f50f19cVendor (CNA)
livebook-dev livebooka552ce8f99ad348ea37061394dc950a0cebdb33eVendor (CNA)
Hex:livebook0.18.7Package registry (OSV)
Hex:livebook0.19.9Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Not on record for this CVE: variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-346 · Origin Validation Error

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records