CVE-2021-41134
Stored XSS in Jupyter nbdime
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Stored XSS in Jupyter nbdime
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.
- Record
CVE-2021-41134- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-0140
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.
- Record
EUVD-2021-0140- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p6rw-44q7-3fw4
Stored XSS in Jupyter nbdime
Impact
Improper handling of user controlled input caused a stored cross-site scripting (XSS) vulnerability. All previous versions of nbdime are affected.
Patches
Security patches will be released for each of the major versions of the nbdime packages since version 1.x of the nbdime python package.
Python
- nbdime 1.x: Patched in v. 1.1.1
- nbdime 2.x: Patched in v. 2.1.1
- nbdime 3.x: Patched in v. 3.1.1
npm
- nbdime 6.x version: Patched in 6.1.2
- nbdime 5.x version: Patched in 5.0.2
- nbdime-jupyterlab 1.x version: Patched in 1.0.1
- nbdime-jupyterlab 2.x version: Patched in 2.1.1
For more information
If you have any questions or comments about this advisory email us at security@ipython.org.
- Record
GHSA-p6rw-44q7-3fw4- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2021-41134- CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 3.5 Low
AV:N/AC:M/Au:S/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
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.
- Record
CVE-2021-41134- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-p6rw-44q7-3fw4
Stored XSS in Jupyter nbdime
Impact
Improper handling of user controlled input caused a stored cross-site scripting (XSS) vulnerability. All previous versions of nbdime are affected.
Patches
Security patches will be released for each of the major versions of the nbdime packages since version 1.x of the nbdime python package.
Python
- nbdime 1.x: Patched in v. 1.1.1
- nbdime 2.x: Patched in v. 2.1.1
- nbdime 3.x: Patched in v. 3.1.1
npm
- nbdime 6.x version: Patched in 6.1.2
- nbdime 5.x version: Patched in 5.0.2
- nbdime-jupyterlab 1.x version: Patched in 1.0.1
- nbdime-jupyterlab 2.x version: Patched in 2.1.1
For more information
If you have any questions or comments about this advisory email us at security@ipython.org.
- Record
GHSA-p6rw-44q7-3fw4- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N - CVSS 3.1
- 8.7 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:11630-1No score
jupyter-nbdime-6.1.2-8.1 on GA media
These are all security issues fixed in the jupyter-nbdime-6.1.2-8.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:11630-1- Updated
- 2026-11-02
OSVPYSEC-2021-428No score
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.
- Record
PYSEC-2021-428- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
nbdimePyPI | before 1.1.1 | 1.1.1 |
nbdimePyPI | 2.0.0 up to 2.1.1 | 2.1.1 |
nbdimePyPI | 3.0.0 up to 3.1.1 | 3.1.1 |
nbdimenpm | before 5.0.2 | 5.0.2 |
nbdimenpm | 6.0.0 up to 6.1.2 | 6.1.2 |
nbdime-jupyterlabnpm | before 1.0.1 | 1.0.1 |
nbdime-jupyterlabnpm | 2.0.0 up to 2.1.1 | 2.1.1 |
nbdimePyPI | before 1.1.1, plus listed versions 0.1.00.1.0.dev0.1.0b10.1.10.1.2 Show 15 moreShow less0.2.00.3.00.4.00.4.11.0.01.0.0rc01.0.0rc11.0.11.0.21.0.31.0.41.0.51.0.61.0.71.1.0 | 1.1.1 |
nbdimePyPI | 2.0.0 up to 2.1.1, plus listed versions 2.1.0 | 2.1.1 |
nbdimePyPI | 3.0.0 up to 3.1.1, plus listed versions 3.1.0 | 3.1.1 |
nbdimePyPI | before 1.1.1, 2.0.0 up to 2.1.1, 3.0.0 up to 3.1.1, plus listed versions 0.1.00.1.0.dev0.1.0b10.1.10.1.2 Show 17 moreShow less0.2.00.3.00.4.00.4.11.0.01.0.0rc01.0.0rc11.0.11.0.21.0.31.0.41.0.51.0.61.0.71.1.02.1.03.1.0 | 1.1.12.1.13.1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41134 is a high vulnerability (CVSS 8.7) in Jupyter Nbdime, published November 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.70%, the 53rd percentile. Fixed in nbdime 1.1.1.
References
github.com/jupyter/nbdime/security/advisories/GHSA-p6rw-44q7-3fw4
nvd.nist.gov/vuln/detail/CVE-2021-41134
suse.com/security/cve/CVE-2021-41134