The Jupyter notebook is a web-based notebook environment for interactive computing. In affected versions untrusted notebook can execute code on load. Jupyter Notebook uses a deprecated version of Google Caja to sanitize user inputs. A public Caja bypass can be used to trigger an XSS when a victim opens a malicious ipynb document in Jupyter Notebook. The XSS allows an attacker to execute arbitrary code on the victim computer using Jupyter APIs.