CVE-2021-41134Network attack vector

Stored XSS via unescaped notebook filename

Published Nov 3, 2021 · Updated Aug 4, 2024

Stored XSS in Project Jupyter nbdime allows remote authenticated users to execute script in another user's browser through a notebook name. The diffNotebookCheckpoint path passes an attacker-controlled filename into NbdimeWidget, whose header template inserted the label as HTML instead of text. Exploitation requires low-privileged access to supply the name and a separate user to view the affected diff, exposing that user's browser data and actions.

CVSS severity6.3
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Project Jupyter nbdime allows remote authenticated users to execute script in another user's browser through a notebook name. The diffNotebookCheckpoint path passes an attacker-controlled filename into NbdimeWidget, whose header template inserted the label as HTML instead of text. Exploitation requires low-privileged access to supply the name and a separate user to view the affected diff, exposing that user's browser data and actions.

The record

CVE
CVE-2021-41134
Published
Nov 3, 2021
Updated
Aug 4, 2024
Vendor
Project Jupyter
Product
nbdime
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 3, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=< 1.0.1 - nbdime-jupyterlab (npm)
  2. Affected versionversion=< 1.1.1 - nbdime (pip)
  3. Affected versionversion=>= 2.0.0, < 2.1.1 - nbdime-jupyterlab (npm)
  4. Affected versionversion=>= 2.0.0 , < 2.1.1 - nbdime (pip)
  5. Affected versionversion=>= 3.0.0, < 3.1.1 - nbdime (pip)
  6. Affected versionversion=< 5.0.2 - nbdime (npm)
  7. Affected versionversion=>= 6.0.0, < 6.1.2 - nbdime (npm)

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Project Jupyter · nbdimeversion=< 1.0.1 - nbdime-jupyterlab (npm); version=< 1.1.1 - nbdime (pip); version=>= 2.0.0, < 2.1.1 - nbdime-jupyterlab (npm); version=>= 2.0.0 , < 2.1.1 - nbdime (pip); version=>= 3.0.0, < 3.1.1 - nbdime (pip); version=< 5.0.2 - nbdime (npm); version=>= 6.0.0, < 6.1.2 - nbdime (npm)

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
6.3GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
8.7GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A: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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

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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