CVE-2026-54338CWE-400denial-of-service

CVE-2026-54338

Medium · published August 8, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
36.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00437 · 36.9th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-08-08T01:17Z
References (2)
https://github.com/jupyterhub/jupyterhub/commit/d6dc595f84b7509969686da31d87d6d69e7fce0a · [email protected]https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-p43p-whwx-q52h · [email protected]
EPSS history
Timeline
  • 07 AUG 20:52Z
    JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login
    cvelistv5