CVE-2023-39968Network attack vector

Open redirect via ambiguous scheme parsing

Published Aug 28, 2023 · Updated Feb 13, 2025

Open redirect in Jupyter Server before 2.7.2 allows remote attackers to send users to arbitrary sites through crafted login links. The _redirect_safe method in jupyter_server/auth/login.py accepted scheme:///host URLs because urllib produced an empty network location while browsers interpreted the host as external. A victim must follow the crafted link and then log in or already have an authenticated session; the resulting redirect affects confidentiality without altering data or interrupting service.

CVSS severity4.3
Medium
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Open redirect in Jupyter Server before 2.7.2 allows remote attackers to send users to arbitrary sites through crafted login links. The _redirect_safe method in jupyter_server/auth/login.py accepted scheme:///host URLs because urllib produced an empty network location while browsers interpreted the host as external. A victim must follow the crafted link and then log in or already have an authenticated session; the resulting redirect affects confidentiality without altering data or interrupting service.

The record

CVE
CVE-2023-39968
Published
Aug 28, 2023
Updated
Feb 13, 2025
Vendor
Project Jupyter
Product
Jupyter Server
Classifications
CWE-601
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 28, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.7.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Project Jupyter · Jupyter Serverversion=< 2.7.2

Published CVSS scores

4.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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