{"action":"Upgrade jupyterhub to 5.5.0 or later.","affected":[{"fixed":"5.5.0","introduced":"0"}],"component":"jupyterhub","cve_ids":["CVE-2026-54338"],"ecosystem":"PyPI","epss":0.00437,"exploited":false,"fixed_versions":["5.5.0"],"ghsa_id":"GHSA-p43p-whwx-q52h","id":"tcs_01M5KFS7WDRW7GQE9PP16JJ1HM","modified_at":"2026-09-29T10:10:48.091771976Z","published_at":"2026-08-25T19:29:19Z","references":["https://osv.dev/vulnerability/GHSA-p43p-whwx-q52h","https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-p43p-whwx-q52h","https://nvd.nist.gov/vuln/detail/CVE-2026-54338","https://github.com/jupyterhub/jupyterhub/commit/d6dc595f84b7509969686da31d87d6d69e7fce0a","https://github.com/jupyterhub/jupyterhub"],"severity":{"label":"medium","score":5.3},"sources":[{"source":"osv","source_id":"GHSA-p43p-whwx-q52h","url":"https://osv.dev/vulnerability/GHSA-p43p-whwx-q52h"}],"summary":"JupyterHub has Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login"}