CVE-2026-73417Network attack vectorHinoki check available

Code execution via unvalidated notebook margin settings

Published Aug 13, 2026 · Updated Aug 13, 2026

Cross-site scripting in JupyterLab 3.3.0 through 4.5.9 and 4.6.0 through 4.6.1 allows attackers to execute code via crafted settings. The notebook tracker inserts sideBySideLeftMarginOverride and sideBySideRightMarginOverride values from overrides.json into style content without validation. Exploitation requires a user to import the file, or write access to a shared settings location loaded automatically, and grants the affected user's notebook, file, server, and connected-kernel access.

CVSS severity8.6
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Cross-site scripting in JupyterLab 3.3.0 through 4.5.9 and 4.6.0 through 4.6.1 allows attackers to execute code via crafted settings. The notebook tracker inserts sideBySideLeftMarginOverride and sideBySideRightMarginOverride values from overrides.json into style content without validation. Exploitation requires a user to import the file, or write access to a shared settings location loaded automatically, and grants the affected user's notebook, file, server, and connected-kernel access.

The record

CVE
CVE-2026-73417
Published
Aug 13, 2026
Updated
Aug 13, 2026
Vendor
Project Jupyter
Product
JupyterLab
Classifications
CWE-116, CWE-79, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 3.3.0, < 4.5.10
  2. Affected versionversion=>= 4.6.0, < 4.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Project Jupyter · JupyterLabversion=>= 3.3.0, < 4.5.10; version=>= 4.6.0, < 4.6.2

Published CVSS scores

8.6GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:L/SC:N/SI:N/SA:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output
CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.002User Execution: Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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