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PYSEC-2026-1481
notebookImpact
The vulnerability depends on user interaction by opening a malicious notebook with Markdown cells, or Markdown file using JupyterLab preview feature.
A malicious user can access any data that the attacked user has access to as well as perform arbitrary requests acting as the attacked user.
Patches
JupyterLab v3.6.8, v4.2.5 and Jupyter Notebook v7.2.2 were patched.
Workarounds
There is no workaround for the underlying DOM Clobbering susceptibility. However, select plugins can be disabled on deployments which cannot update in a timely fashion to minimise the risk. These are:
@jupyterlab/mathjax-extension:plugin- users will loose ability to preview mathematical equations@jupyterlab/markdownviewer-extension:plugin- users will loose ability to open Markdown previews@jupyterlab/mathjax2-extension:plugin(if installed with optionaljupyterlab-mathjax2package) - an older version of the mathjax plugin for JupyterLab 4.x
To disable these extensions run:
jupyter labextension disable @jupyterlab/markdownviewer-extension:plugin
jupyter labextension disable @jupyterlab/mathjax-extension:plugin
jupyter labextension disable @jupyterlab/mathjax2-extension:plugin
To confirm that the plugins were disabled run:
jupyter labextension list
References
None
Notes
This change has a potential to break rendering of some markdown. There is a setting in Sanitizer which allows to revert to the previous sanitizer settings (allowNamedProperties).
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a low impact on the integrity of the data. There is a low impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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