CVE-2024-39700: Jupyter JupyterLab RCE Vulnerability

CVE-2024-39700 Overview

CVE-2024-39700 is a critical Remote Code Execution (RCE) vulnerability affecting the JupyterLab extension template, a copier template used for creating JupyterLab extensions. Repositories created using this template with the test option include an update-integration-tests.yml GitHub Actions workflow that contains an RCE vulnerability. This flaw allows attackers to execute arbitrary code through malicious pull requests from untrusted users, potentially compromising the entire development pipeline and downstream users of affected extensions.

Critical Impact

Attackers can achieve Remote Code Execution through malicious pull requests, potentially compromising CI/CD pipelines and supply chain integrity of JupyterLab extensions.

Affected Products

• Jupyter JupyterLab Extension Template (versions prior to 4.3.0)
• Repositories created using the JupyterLab extension template with test option enabled
• GitHub Actions workflows containing vulnerable update-integration-tests.yml

Discovery Timeline

• 2024-07-16 - CVE-2024-39700 published to NVD
• 2025-09-04 - Last updated in NVD database

Technical Details for CVE-2024-39700

Vulnerability Analysis

This vulnerability stems from improper handling of untrusted input in the update-integration-tests.yml GitHub Actions workflow. The workflow, included in repositories generated from the JupyterLab extension template when the test option is selected, fails to properly sanitize or restrict code execution contexts. When a pull request is opened against a repository using this vulnerable workflow, the actions may execute using code from the main branch at the time the pull request was created, allowing an attacker to inject malicious code that gets executed with repository permissions.

The vulnerability is classified under CWE-94 (Improper Control of Generation of Code), indicating that the workflow allows external actors to inject and execute arbitrary code within the GitHub Actions runner environment.

Root Cause

The root cause is the insecure configuration of the GitHub Actions workflow file update-integration-tests.yml. The workflow lacks proper isolation and input validation when processing pull requests from external contributors. This allows untrusted code from forked repositories or external pull requests to be executed within the context of the target repository's CI/CD environment, effectively granting unauthorized code execution capabilities.

Attack Vector

The attack vector is network-based, requiring no privileges or user interaction for exploitation. An attacker can exploit this vulnerability by:

1. Forking a repository that uses the vulnerable JupyterLab extension template
2. Creating a malicious pull request containing code designed to execute during the workflow run
3. Exploiting the workflow's execution context to run arbitrary commands with the repository's GitHub Actions permissions

This could lead to secrets exfiltration, repository compromise, malicious code injection into releases, or lateral movement within the organization's GitHub infrastructure.

The vulnerability mechanism involves the GitHub Actions workflow processing untrusted pull request content without proper sandboxing. The workflow configuration allows code execution from the pull request branch within the context of the main repository's permissions. For detailed technical information on the vulnerable workflow configuration, refer to the GitHub Security Advisory GHSA-45gq-v5wm-82wg.

Detection Methods for CVE-2024-39700

Indicators of Compromise

• Unexpected or unauthorized workflow runs triggered by external pull requests
• Modified or suspicious update-integration-tests.yml workflow files in repositories
• Unauthorized access to repository secrets or environment variables
• Unusual GitHub Actions runner activity or resource consumption
• Unexpected commits or releases from CI/CD processes

Detection Strategies

• Audit all repositories created from the JupyterLab extension template for the presence of vulnerable update-integration-tests.yml files
• Monitor GitHub Actions logs for workflow executions triggered by untrusted pull requests
• Review pull request activity from unknown or untrusted contributors targeting repositories with the test option enabled
• Implement GitHub Actions workflow analysis to detect insecure patterns in CI/CD configurations

Monitoring Recommendations

• Enable GitHub Actions audit logging and regularly review workflow execution history
• Configure alerts for workflow runs triggered by pull requests from first-time contributors
• Monitor for any modifications to workflow files in the .github/workflows/ directory
• Implement code scanning to detect insecure GitHub Actions patterns across your organization

How to Mitigate CVE-2024-39700

Immediate Actions Required

• Upgrade the JupyterLab extension template to the latest version immediately
• Temporarily disable GitHub Actions on affected repositories while implementing the upgrade
• Rebase all open pull requests from untrusted users to prevent exploitation using cached vulnerable workflow versions
• Review recent workflow runs for signs of exploitation or unauthorized code execution

Patch Information

The JupyterLab maintainers have released a security fix in commit 035e78c1c65bcedee97c95bb683abe59c96bc4e6. Extension authors should upgrade their template to the latest version by following the vendor guidance. When upgrading, users who have made customizations to update-integration-tests.yml should accept the overwrite of this file and re-apply their changes afterward. For repositories upgrading from template versions prior to 4.3.0, consider deferring changes to the release workflow as it requires additional configuration. Detailed patch information is available in the GitHub Commit Update.

Workarounds

• Temporarily disable GitHub Actions on repositories using the vulnerable template until the upgrade can be applied
• Restrict workflow permissions by configuring minimal required permissions in workflow files
• Implement branch protection rules requiring approval for all pull requests before workflow execution
• Use the pull_request_target event with caution or switch to pull_request with restricted checkout patterns

# Disable GitHub Actions temporarily for a repository
# Navigate to repository Settings > Actions > General
# Select "Disable Actions" until the template upgrade is complete

# After upgrading, verify the workflow file has been updated
git diff main..HEAD -- .github/workflows/update-integration-tests.yml