{"id":"CVE-2026-73626","aliases":["BIT-jupyterlab-2026-73626","GHSA-whvh-wf3x-g77j"],"url":"https://o3.security/vulnerability/CVE-2026-73626","summary":"JupyterLab before 4.6.2 Authentication Bypass via PyPIExtensionManager","details":"The extension allowlist/blocklist check inside `PyPIExtensionManager.install()` was not enforced due to a missing await. For purposes of JupyterLab this was a secondary defense-in-depth check: `install()` was intended to enforce the allowlist/blocklist itself for any future uses and users calling this method directly (in addition to the separate check handling requests arriving through the HTTP API).  The only runtime symptom was a `RuntimeWarning: coroutine 'is_install_allowed' was never awaited.`\n\nThis has security implications only for deployments that combine all of the following:\n- a custom extension or downstream integration that imports `PyPIExtensionManager` and calls `install()` directly with a package name influenced by untrusted user input (the stock JupyterLab HTTP handler is not affected - it performs its own awaited allowlist check before calling `install()`);\n- an allowlist/blocklist configured with the intent of restricting which packages users can install;\n- the (default) PyPI Extension Manager enabled; and\n- kernels and terminals disabled or delegated to remote hosts, so that the custom extension's `install()` call is the only available package-install vector (otherwise a user with kernel access can install packages directly regardless of this check)\n\n### Impact\n\nLow. No exposure for stock JupyterLab: the HTTP API and Extension Manager UI enforce the listing through a separate, correctly awaited check. The gap affected only custom extensions or downstream integrations that called the public `install()` method directly and relied on it to self-enforce.\n\n### Patches\n\nJupyterLab [`v4.6.2`](https://github.com/jupyterlab/jupyterlab/releases/tag/v4.6.2) and [`v4.5.10`](https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.10) contain the patch.\n\nUsers of applications that depend on JupyterLab, such as Notebook v7+, should update `jupyterlab` package too.\n\n### Workarounds\n\nNo action is required for deployments that only expose extension management through the JupyterLab HTTP API / Extension Manager UI, as that path was already enforcing the listing via the handler's own check. Deployments wanting to disable programmatic extension installation entirely can switch to the read-only extension manager:\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\" />","published":"2026-08-13T11:28:25.551Z","modified":"2026-10-21T02:59:17.424660972Z","cvss":null,"epss":{"score":0.00214,"percentile":0.11978,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"jupyterlab","fixedVersion":"4.6.2"},{"ecosystem":"PyPI","name":"jupyterlab","fixedVersion":"4.5.10"}],"fix":{"url":"https://github.com/jupyterlab/jupyterlab/pull/19184","label":"jupyterlab/jupyterlab#19184"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73626.json"},{"type":"ADVISORY","url":"https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-whvh-wf3x-g77j"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-73626"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/jupyterlab-before-authentication-bypass-via-pypiextensionmanager"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/pull/19184"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/pull/19185"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/pull/19186"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/commit/be9303f5bcd5308eaeae953c5a3c903046682c2c"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/commit/f1beab4a2027af4719d6edc07d52d6cf5a39a432"},{"type":"PACKAGE","url":"https://github.com/jupyterlab/jupyterlab"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.10"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/releases/tag/v4.6.2"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:59:17.424660972Z"}}