CVE-2026-54338

MEDIUM

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

Title source: cna
STIX 2.1

Description

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.

References (2)

Core 2

Scores

CVSS v3 5.3
EPSS 0.0028
EPSS Percentile 20.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Details

CWE
CWE-400
Status published
Products (1)
jupyterhub/jupyterhub < 5.5.0JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks.
Published Aug 07, 2026
Tracked Since Aug 08, 2026