CVE-2026-54338: medium-severity vulnerability in jupyterhub
JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 5.3epss 0.4%
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 · jupyterhubRelated CVEs — jupyterhub
In the same product, most dangerous first.
CVE-2021-41247LOWincomplete logout in JupyterHubEPSS 0.8%CVE-2024-41942HIGHJupyterHub has a privilege escalation vulnerability with the `admin:users` scopeEPSS 0.6%CVE-2024-28233HIGHXSS in JupyterHub via Self-XSS leveraged by Cookie TossingEPSS 0.3%CVE-2026-108752LOWJupyterHub through 6.0.1 OAuth Client ID Collision via Unescaped HyphenEPSS 0.2%CVE-2026-33709MEDIUMJupyterHub has an Open Redirect VulnerabilityEPSS 0.2%CVE-2026-40864MEDIUMJupyterHub: Cross-origin form POSTs bypass XSRFEPSS 0.1%