CVE-2021-41134

What it is

nbdime provides tools for diffing and merging of Jupyter Notebooks. In affected versions a stored cross-site scripting (XSS) issue exists within the Jupyter-owned nbdime project. It appears that when reading the file name and path from disk, the extension does not sanitize the string it constructs before returning it to be displayed. The diffNotebookCheckpoint function within nbdime causes this issue. When attempting to display the name of the local notebook (diffNotebookCheckpoint), nbdime appears to simply append .ipynb to the name of the input file. The NbdimeWidget is then created, and the base string is passed through to the request API function. From there, the frontend simply renders the HTML tag and anything along with it. Users are advised to patch to the most recent version of the affected product.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account, but needs a user to act. High risk of data exposure, data tampering.

Exploit odds

0.7% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-11-03 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:07 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.7% in the next 30 days (EPSS).
• Severity: 8.7 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-11-03 18:15 UTC

Last modified

2026-06-17 04:07 UTC

Exploit probability

0.7% · EPSS, next 30 days

Weakness

CWE-79 · Cross-site scripting

Record status

Modified

Affected

• Jupyter Nbdime < 1.1.1
• Jupyter Nbdime < 2.1.1
• Jupyter Nbdime ≤ 3.1.1
• Jupyter Nbdime < 5.0.2
• Jupyter Nbdime < 6.1.2
• Jupyter nbdime-jupyterlab < 1.0.1
• Jupyter nbdime-jupyterlab < 2.1.1

Attack profile CVSS 3.1 · 8.7

Attack vector

Network

Complexity

Low

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

High

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-41134.md and follow it. Check whether this project is affected by CVE-2021-41134. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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