Jupyter Server Enterprise Gateway up to 3.2.x Kubernetes Manifest Renderer KERNEL_XXX special elements used in a template engine

Summaryinfo

A vulnerability marked as critical has been reported in Jupyter Server Enterprise Gateway up to 3.2.x. Affected by this issue is some unknown functionality of the component Kubernetes Manifest Renderer. Performing a manipulation of the argument KERNEL_XXX results in improper neutralization of special elements used in a template engine. This vulnerability is reported as CVE-2026-44181. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, was found in Jupyter Server Enterprise Gateway up to 3.2.x. This affects an unknown code of the component Kubernetes Manifest Renderer. The manipulation of the argument KERNEL_XXX with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. CWE is classifying the issue as CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-44181 since 05/05/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1221 for this issue.

Upgrading to version 3.3.0 eliminates this vulnerability.

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Productinfo

Vendor

• Jupyter Server

Name

• Enterprise Gateway

Version

• 3.0
• 3.1
• 3.2

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CPE 2.2info

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