5.3

CVE-2026-54338: jupyterhub Uncontrolled Resource Consumption

CVSS: 5.3v3.1MediumAwaiting analysis
AliasesGHSA-p43p-whwx-q52hBIT-jupyterhub-2026-54338PYSEC-2026-3853
Published 07-08-2026Last modified 11-08-2026
Open JSON

Vulnerability summary

CVE-2026-54338 is a medium (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in jupyterhub. EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 36.6% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.44%
0%100%
Low · +0.15 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 07-08-2026
    PublishedVulnerability first disclosed.
  2. 11-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.44%

Chance of exploitation in the next 30 days

Percentile

37%

Versus all other CVEs

30-day change

+0.15 pp

From 0.28% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.44%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • jupyterhubAll versions (No fix recorded)
Jupyterhub1 product
  • jupyterhub< 5.5.0JupyterHub 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.
PyPI1 product
  • jupyterhub< 5.5.0
Ubuntu1 product
  • jupyterhubAll versions (No fix recorded)

4 vendors · 4 products

References

9 links