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CVE-2026-54338mediumCWE-400

JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login

10Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.3
exploitation probability
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
jupyterhub · jupyterhub