Publish GHSA-37w4-hwhx-4rc4

Author: advisory-database[bot]

advisories/github-reviewed/2026/05/GHSA-37w4-hwhx-4rc4/GHSA-37w4-hwhx-4rc4.json

@@ -1,13 +1,13 @@
 {
   "schema_version": "1.4.0",
   "id": "GHSA-37w4-hwhx-4rc4",
-  "modified": "2026-05-05T20:53:18Z",
+  "modified": "2026-05-21T00:41:39Z",
   "published": "2026-05-05T20:53:18Z",
   "aliases": [
     "CVE-2026-42266"
   ],
-  "summary": "JupyterHub has an Extension Manager API/GUI Policy Discrepancy, allowing 3rd party (malicious) extensions install via POST request",
-  "details": "The allow-list of extensions that can be installed from PyPI Extension Manager (`allowed_extensions_uris`) is not correctly enforced by JupyterLab prior to 4.5.X. The PyPI Extension Manager was not contained to packages listed on the default PyPI index.\n\nThis has security implications for deployments that:\n- have allow-listed specific extensions with aim to prevent users from installing packages\n- have the kernel and terminals disabled or delegated to remote hosts (thus no access to install packages in the single-user server environment)\n- have multi-tenant deployments that is not configured for untrusted users (as per documented on JupyterHub https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html)\n- have the (default) PyPI Extension Manger enabled\n\n### Impact\n\nAn authenticated attacker - such as a student in a shared JupyterHub environment or a user in a multi-tenant JupyterLab deployment - can escalate their privileges. This might allow for data exfiltration, lateral movement within the network, and persistent compromise of the server infrastructure.\n\n### Patches\n\nJupyterLab [`v4.5.7`](https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7) contains the patch.\n\nUsers of applications that depend on JupyterLab, such as Notebook v7+, should update `jupyterlab` package too.\n\n### Workarounds\n\nSwitch to read-only extension manager by adding the following command line option:\n\n```bash\n--LabApp.extension_manager=readonly\n```\n\nor the following traitlet:\n\n```python\nc.LabApp.extension_manager = 'readonly'\n```\n\nYou can confirm that the read-only manager is in use from GUI:\n\n<img width=\"293\" height=\"293\" alt=\"image\" src=\"https://github.com/user-attachments/assets/8016c809-633e-4ed0-a5bc-6bc4793caa0f\" />\n\nNote: configuration of a PyPI proxy with allow-listed packages is not sufficient to protect from this vulnerability.\n\n### Resources\n\n- allow-list https://jupyterlab.readthedocs.io/en/stable/user/extensions.html#listing-configuration\n- https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html\n- https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations",
+  "summary": "JupyterLab has an Extension Manager API/GUI Policy Discrepancy, allowing 3rd party (malicious) extensions install via POST request",
+  "details": "The allow-list of extensions that can be installed from PyPI Extension Manager (`allowed_extensions_uris`) is not correctly enforced by JupyterLab prior to 4.5.7. The PyPI Extension Manager was not contained to packages listed on the default PyPI index.\n\nThis has security implications for deployments that:\n- have allow-listed specific extensions with aim to prevent users from installing packages\n- have the kernel and terminals disabled or delegated to remote hosts (thus no access to install packages in the single-user server environment)\n- have multi-tenant deployments that is not configured for untrusted users (as per documented on JupyterHub https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html)\n- have the (default) PyPI Extension Manager enabled\n\n### Impact\n\nAn authenticated attacker - such as a student in a shared JupyterHub environment or a user in a multi-tenant JupyterLab deployment - can escalate their privileges. This might allow for data exfiltration, lateral movement within the network, and persistent compromise of the server infrastructure.\n\n### Patches\n\nJupyterLab [`v4.5.7`](https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.7) contains the patch.\n\nUsers of applications that depend on JupyterLab, such as Notebook v7+, should update `jupyterlab` package too.\n\n### Workarounds\n\nSwitch to read-only extension manager by adding the following command line option:\n\n```bash\n--LabApp.extension_manager=readonly\n```\n\nor the following traitlet:\n\n```python\nc.LabApp.extension_manager = 'readonly'\n```\n\nYou can confirm that the read-only manager is in use from GUI:\n\n<img width=\"293\" height=\"293\" alt=\"image\" src=\"https://github.com/user-attachments/assets/8016c809-633e-4ed0-a5bc-6bc4793caa0f\" />\n\nNote: configuration of a PyPI proxy with allow-listed packages is not sufficient to protect from this vulnerability.\n\n### References\n\n- allow-list https://jupyterlab.readthedocs.io/en/stable/user/extensions.html#listing-configuration\n- https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html\n- https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations",
   "severity": [
     {
       "type": "CVSS_V3",
@@ -43,6 +43,10 @@
       "type": "WEB",
       "url": "https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-37w4-hwhx-4rc4"
     },
+    {
+      "type": "ADVISORY",
+      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42266"
+    },
     {
       "type": "PACKAGE",
       "url": "https://github.com/jupyterlab/jupyterlab"
@@ -63,12 +67,12 @@
   "database_specific": {
     "cwe_ids": [
       "CWE-20",
-      "CWE-602",
-      "CWE-88"
+      "CWE-88",
+      "CWE-602"
     ],
     "severity": "HIGH",
     "github_reviewed": true,
     "github_reviewed_at": "2026-05-05T20:53:18Z",
-    "nvd_published_at": null
+    "nvd_published_at": "2026-05-13T16:16:47Z"
   }
 }