CyberSecBulletin
CVE-2026-68746NVD status: Modified

livebook: Not Failing Securely

Published Updated By the CyberSecBulletin desk

CVE-2026-68746 is a high-severity not failing securely 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 attacker with a low-privileged account, without any action from a user. The record lists versions 0.19.9, 0.19.9-cuda12, 2d3a2c710c880abd24a2bc888d3cf5239d98cf72 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 0.95% chance of exploitation within 30 days, higher than 62% of scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update livebook to 0.19.9 or 0.19.9-cuda12 or 2d3a2c710c880abd24a2bc888d3cf5239d98cf72 or d374e90647edbb00286bfee9182c0161d29a8e07, whichever matches your release line, or a later version.
  2. Read the advisory on cna.erlef.org for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Livebook-devlivebook0.19.7 up to, but not including, 0.19.9; 0.19.7-cuda12 up to, but not including, 0.19.9-cuda12; fc2c87c6b0276705281842acbe17142d1ac4d555 up to, but not including, 2d3a2c710c880abd24a2bc888d3cf5239d98cf72; 6592a0faf973943a3c8de5e9871a4c9493d78671 up to, but not including, d374e90647edbb00286bfee9182c0161d29a8e07; 82e0b8009a59298dbad8638e01dbc9b0d7798353 up to, but not including, d6d0dfa746b172540442852f74de4a9deacc433b0.19.9, 0.19.9-cuda12, 2d3a2c710c880abd24a2bc888d3cf5239d98cf72, d374e90647edbb00286bfee9182c0161d29a8e07, d6d0dfa746b172540442852f74de4a9deacc433b

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
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
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:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 4.07.7HighCNA
CVSS 3.18.8HighNVD

Official description

Not Failing Securely ('Failing Open') vulnerability in livebook-dev livebook allows an unauthenticated network client to obtain full access to a Livebook server that enforces identity through Livebook Teams. A Livebook Agent or App Server connected to Livebook Teams caches the identifier of the deployment group it belongs to, and resolves that identifier against a locally cached list of deployment groups on every request in order to decide whether Teams identity enforcement is active. Livebook.Hubs.TeamClient.handle_call/3 in lib/livebook/hubs/team_client.ex does not distinguish a deployment group that could not be resolved from one that was resolved with identity enforcement switched off: the clause matches only the case where a group was found with enforcement enabled, and falls through to a catch-all that reports enforcement as switched off for everything else. The two neighbouring functions that decide user and application access resolve the same identifier and treat the same unresolved result as a denial. When the identity status is reported as switched off, Livebook.ZTA.LivebookTeams.authenticate/3 in lib/livebook/zta/livebook_teams.ex returns empty identity metadata and allows the request to continue instead of halting it. LivebookWeb.UserPlug.build_current_user/3 merges that empty metadata into a newly built user, whose access type defaults to full access, and LivebookWeb.AuthPlug.authorized?/1 grants access to any user holding full access. The cached identifier becomes unresolvable when the deployment group it refers to is deleted while the agent is not connected to receive the change, most concretely when a deployment group is deleted during the window in which an agent is disconnected or reconnecting. The client removes the group from its cached list without clearing the identifier that refers to it. Any client able to reach the affected server over the network is then granted the same access as a fully privileged member of the organisation, including the ability to read notebooks and configured secrets, execute code on the server's runtime, and disrupt its operation. This issue affects livebook: from 0.19.7 before 0.19.9.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Not Failing Securely

When the product encounters an error condition or failure, its design requires it to fall back to a state that is less secure than other options that are available, such as selecting the weakest encryption algorithm or using the most permissive access control restrictions.

How developers prevent this class of flaw

  • Subdivide and allocate resources and components so that a failure in one part does not affect the entire product.

More Not Failing Securely vulnerabilities (CWE-636)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Other vulnerabilities in livebook

All livebook vulnerabilities

Recent Not Failing Securely vulnerabilities

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