CVE-2026-40171

HIGH EPSS 37.6%
Published May 6, 20261mo ago · Modified Jun 17, 20262w ago
8.4 CVSS 4.0
High
Find Similar
Published May 6, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

Description

In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with attacker-controlled notebook content to steal authentication tokens with a single click. An attacker can craft a malicious notebook file containing elements that appear indistinguishable from legitimate controls and trigger execution when a user interacts with them. Successful exploitation allows theft of the user's authentication token and complete takeover of the Jupyter session through the REST API, including reading files, creating or modifying files, accessing kernels to execute arbitrary code, and creating terminals for shell access. This issue has been fixed in Notebook 7.5.6, JupyterLab 4.5.7, @jupyter-notebook/help-extension 7.5.6, and @jupyterlab/help-extension 4.5.7. As a workaround, disable the affected help extensions or set allowCommandLinker to false in the sanitizer configuration.

CVSS Details

Base Score
8.4
Exploitability
Impact
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required High
User Interaction A
Scope X

Threat Intelligence

EPSS Exploit Probability
37.6% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-79 Cross-site Scripting Injection

References 1

  • github.com https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.