{"id":"CVE-2021-41247","aliases":["BIT-jupyterhub-2021-41247","DEBIAN-CVE-2021-41247","EUVD-2021-0105","GHSA-cw7p-q79f-m2v7","PYSEC-2021-386"],"status":"published","title":"incomplete logout in JupyterHub","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","severity":{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00804,"percentile":0.57011,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-613"],"published":"2021-11-04T17:15:11Z","modified":"2026-10-23T18:03:39Z","fixes":[{"ecosystem":"PyPI","package":"jupyterhub","fixed_in":["1.5.0"],"sources":["ghsa","osv"]},{"ecosystem":"Bitnami","package":"jupyterhub","fixed_in":["1.5.0"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"jupyterhub","fixed_in":["2.0.0+ds1-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"jupyterhub","fixed_in":["2.0.0+ds1-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"jupyterhub","fixed_in":["2.0.0+ds1-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"jupyterhub","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.0"},{"fixed":"1.5.0"}]}]},{"source":"osv","ecosystem":"Bitnami","package":"jupyterhub","ranges":[{"type":"SEMVER","events":[{"introduced":"1.0.0"},{"fixed":"1.5.0"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"jupyterhub","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.0+ds1-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"jupyterhub","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.0+ds1-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"jupyterhub","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.0+ds1-1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"jupyterhub","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.0"},{"fixed":"1.5.0"}]}],"versions":["1.0.0","1.1.0","1.1.0b1","1.2.0","1.2.0b1","1.2.1","1.2.2","1.3.0","1.4.0","1.4.1","1.4.2"]},{"source":"osv","ecosystem":"PyPI","package":"jupyterhub","ranges":[{"type":"GIT","events":[{"introduced":"0"},{"fixed":"5ac9e7f73a6e1020ffddc40321fc53336829fe27"}]},{"type":"ECOSYSTEM","events":[{"introduced":"1.0.0"},{"fixed":"1.5.0"}]}],"versions":["1.0.0","1.1.0","1.1.0b1","1.2.0","1.2.0b1","1.2.1","1.2.2","1.3.0","1.4.0","1.4.1","1.4.2"]}],"products":[{"vendor":"jupyter","product":"jupyterhub"},{"vendor":"jupyterhub","product":"jupyterhub"}],"references":[{"url":"https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-cw7p-q79f-m2v7","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/jupyterhub/jupyterhub/commit/5ac9e7f73a6e1020ffddc40321fc53336829fe27","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-41247","tags":["web","advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/jupyterhub/PYSEC-2021-386.yaml","tags":["web"]},{"url":"https://github.com/advisories/GHSA-cw7p-q79f-m2v7"},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-41247","tags":["advisory"]},{"url":"https://github.com/jupyterhub/jupyterhub","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-41247","title":"incomplete logout in JupyterHub","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T17:15:11Z","modified":"2024-08-04T03:08:31.58Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T14:32:59.105382Z"}],"euvd":[{"id":"EUVD-2021-0105","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T17:15:11Z","modified":"2024-08-04T03:08:31Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-03T03:24:18.784846Z"}],"ghsa":[{"id":"GHSA-cw7p-q79f-m2v7","title":"incomplete JupyterHub logout with simultaneous JupyterLab sessions","description":"### Impact\n\nUsers of JupyterLab with JupyterHub who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place.\n\n### Patches\n\nUpgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment.\n\n### Workarounds\n\nThe only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-08T18:02:37Z","modified":"2024-09-24T20:50:55Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"},{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T14:38:06.29677Z"}],"nvd":[{"id":"CVE-2021-41247","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T18:15:08.707Z","modified":"2026-06-17T04:08:10.207Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T14:07:00.549994Z"}],"osv":[{"id":"CVE-2021-41247","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T18:15:08.707Z","modified":"2026-10-20T10:53:58.730156029Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:44:21.557945Z"},{"id":"DEBIAN-CVE-2021-41247","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T18:15:08.707Z","modified":"2026-10-23T18:03:39.256363112Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T15:45:35.521549Z"},{"id":"GHSA-cw7p-q79f-m2v7","title":"incomplete JupyterHub logout with simultaneous JupyterLab sessions","description":"### Impact\n\nUsers of JupyterLab with JupyterHub who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place.\n\n### Patches\n\nUpgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment.\n\n### Workarounds\n\nThe only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-08T18:02:37Z","modified":"2026-07-08T06:28:53.199283056Z","cvss":[{"version":"3.1","score":3.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:N","level":"low"},{"version":"4.0","score":5.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N","level":"medium"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T15:46:45.639885Z"},{"id":"BIT-jupyterhub-2021-41247","title":"incomplete logout in JupyterHub","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2024-03-06T10:53:59.095Z","modified":"2026-09-08T08:48:23.860504351Z","updated_at":"2026-11-02T15:28:31.782692Z"},{"id":"PYSEC-2021-386","description":"JupyterHub is an open source multi-user server for Jupyter notebooks. In affected versions users who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place. Upgrade to JupyterHub 1.5. For distributed deployments, it is jupyterhub in the _user_ environment that needs patching. There are no patches necessary in the Hub environment. The only workaround is to make sure that only one JupyterLab tab is open when you log out.","status":"published","published":"2021-11-04T18:15:00Z","modified":"2023-12-06T01:01:35.608761Z","updated_at":"2026-11-02T15:52:52.682031Z"}]}}