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21Track

JupyterLab Desktop: One-Click Jupyter Server Token Leak leading to Remote Code Execution

jupyterlab-desktop · CVE-2026-86044 EUVD-2026-118461
0 news outlets0 CERTs and agencies0 research labs

Assessment: Track

SSVC decision points: exploitation none, automatable no, technical impact total, deployment low.

What is it?

JupyterLab Desktop is the cross-platform desktop application for JupyterLab. Prior to 4.6.2-1, JupyterLab Desktop exposed getServerInfo to the renderer without confirming that the current page still had the local Jupyter server origin. In a local managed session using JupyterLab before 4.4.8, an attacker can place a crafted MathJax link in an untrusted notebook. If a victim opens the notebook and clicks the link, the existing renderer navigates to an attacker-controlled site while retaining access to the preload bridge. The site can call getServerInfo to obtain the local server URL and authentication token, then use the Jupyter REST API to create and trust a notebook that executes arbitrary code as the victim. Users whose environment already uses JupyterLab 4.4.8 or later are unaffected because the corrected link handling breaks the first step of the chain. This vulnerability is fixed in 4.6.2-1.

Evidence

No coverage recorded yet.

Exploitation

  • Exploit code published (not verified by us)
  • Exploited in the wild (confirmed by a source)
  • Listed as known exploited (CISA KEV)
CVSS
9.6
EPSS
0.3%
First seen
1 d ago
Status
corroborated

All jupyterlab vulnerabilities