Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1359 CNY

100%
Buy Us a Coffee

CVE-2026-54338— JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login

Quick assessment

Affected
jupyterhub jupyterhub
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

JupyterHub是JupyterHub组织开源的一款用于Jupyter的多用户服务器。 JupyterHub 5.5.0之前版本存在资源管理错误漏洞，该漏洞源于基于表单的登录验证器输入验证不当，可能将无界攻击者控制的用户名放入失败登录日志中，导致未经身份验证的攻击者消耗日志和存储资源。

CVSS 5.3 · Medium EPSS 0.44% · P36

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 1

VendorProduct Version RangeStatus
jupyterhub jupyterhub < 5.5.0JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-54338

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
JupyterHub: Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
JupyterHub 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
JupyterHub是JupyterHub组织开源的一款用于Jupyter的多用户服务器。 JupyterHub 5.5.0之前版本存在资源管理错误漏洞，该漏洞源于基于表单的登录验证器输入验证不当，可能将无界攻击者控制的用户名放入失败登录日志中，导致未经身份验证的攻击者消耗日志和存储资源。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
jupyterhub 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 una -

II. Public POCs for CVE-2026-54338

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-54338

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-54338 (1)

Vendor Advisories for CVE-2026-54338 (1)

IV. Related Vulnerabilities

Same product: jupyterhub
Same vendor: jupyterhub
Same weakness: CWE-400

V. Comments for CVE-2026-54338

No comments yet

Leave a comment