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CVE-2026-42557

37
FAUCET Score

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with a pre-saved HTML cell output containing a deceptive button can trigger arbitrary JupyterLab commands - including arbitrary code execution - on a single user click, without any code being submitted for execution by the user. This vulnerability is fixed in 4.5.7.

First published: May 13, 2026Last modified: May 13, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 4.5.7CPE matchmatch criteria
cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:*
>= 7.0.0, < 7.5.6CPE matchmatch criteria
cpe:2.3:a:jupyter:notebook:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 4.0

8.6HIGH

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

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
ACTIVE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
HIGH
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.35%
Probability of exploitation in next 30 days
EPSS Percentile
27.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0035 is in the 31st percentile among its peer group of 834 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.8 Bluesky, 0.5 Mastodon, and 1.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.1 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (3)

pippatch availablevia ghsa
Product: jupyterlabFixed in: 4.5.7
pippatch availablevia ghsa
Product: notebookFixed in: 7.5.6
github_advisoryworkaround availablevia nvd_reference
View patch

Vendor Advisories (1)

pipGHSA-mqcg-5x36-vfcghigh

JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content

May 6, 2026

References

access.redhat.com / errata/RHSA-2026:43038
access.redhat.com / security/cve/CVE-2026-42557
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-42557.json
github.com / jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg
MitigationVendor Advisory