CVE-2026-44181: Jupyter Enterprise Gateway: Jinja2 Template Server Side Template Injection results in Remote Code Execution

Severity: critical (CVSS 10.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-16 · updated 2026-10-24
Weakness: CWE-1336

Description

Jupyter Enterprise Gateway launches remote Jupyter Notebook kernels across distributed clusters like Apache Spark, Kubernetes, and Docker Swarm. In versions 2.0.0rc2 and above, prior to 3.3.0, the environment variables (KERNEL_XXX) used during the rendering of the Kubernetes manifest are vulnerable to Server Side Template Injection (SSTI). By including Jinja2 template expressions it is possible to execution Python code and OS Commands in the Enterprise Gateway service. The code can use or steal the Kubernetes service account token, which can steal Kubernetes secrets and be used to fully compromise the Kubernetes cluster by scheduling a privileged pod or a pod with a hostPath volume mount. This issue has been fixed in version 3.3.0.

Affected products

jupyter-server enterprise_gateway: from 2.1.0 before 3.3.0; 2.0.0, 2.0.0-rc2 — fixed in 3.3.0

How to fix

Upgrade to a fixed version: jupyter-server enterprise_gateway 3.3.0. Check the vendor advisory for mitigations.

References

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