CVE-2026-54338 — JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbou…
Published: 2026-08-07 · CVSS: 5.3 · CVSS 3.1
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbounded attacker-controlled username in failed-login logs, allowing an unauthenticated attacker to consume logging and storage resources. This issue is fixed in version 5.5.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7