CVE-2026-67338Network attack vectorHinoki check available

Stored XSS via unsanitized package metadata URI

Published Aug 1, 2026 · Updated Aug 1, 2026

Stored XSS in the Extension Manager in Project Jupyter JupyterLab before 4.5.9 allows remote attackers to run script via package metadata. The PyPI backend copies a package project URL into homepage_url, and widget.tsx renders it as an href without restricting the javascript protocol. Execution requires the default PyPI-backed Extension Manager to show the package and a user to click its extension name; the script runs in the JupyterLab origin.

CVSS severity5.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stored XSS in the Extension Manager in Project Jupyter JupyterLab before 4.5.9 allows remote attackers to run script via package metadata. The PyPI backend copies a package project URL into homepage_url, and widget.tsx renders it as an href without restricting the javascript protocol. Execution requires the default PyPI-backed Extension Manager to show the package and a user to click its extension name; the script runs in the JupyterLab origin.

The record

CVE
CVE-2026-67338
Published
Aug 1, 2026
Updated
Aug 1, 2026
Vendor
Project Jupyter
Product
JupyterLab
Classifications
CWE-84, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 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=0 <4.5.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Project Jupyter · JupyterLabversion=0 <4.5.9

Published CVSS scores

6.1VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1Red HatCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N

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-84Improper Neutralization of Encoded URI Schemes in a Web Page
T1204.001Malicious Link

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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