CVE-2025-61669: Jupyter server Jupyter Server Has An Open Vulnerability

MODERATE
Advisory Identifier: GHSA-qh7q-6qm3-653w
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CWE-601
Published
Advisory Summary

CVE-2025-61669 is a MODERATE jupyter server has an open vulnerability (CWE-601: URL Redirection to Untrusted Site ('Open Redirect')) affecting Jupyter server libraries in the PyPI ecosystem. The issue involves jupyter server has an open redirection vulnerability in `next` query parameter. Remediation is available by upgrading affected packages to version 2.18.0.

CVE-2025-61669 at a Glance

CVE Identifier CVE-2025-61669
GHSA Identifier GHSA-qh7q-6qm3-653w
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Affected Product Jupyter server
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2025-61669

To remediate this vulnerability, upgrade all affected Jupyter server dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

jupyter-server fixed: 2.18.0 
pip install jupyter-server>=2.18.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show jupyter-server

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2025-61669, inspect your installed packages using pip:

pip show jupyter-server

Analyze the terminal output to locate any version of Jupyter server in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.18.0), your application is affected.

Note: The pip show jupyter-server command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect'), where the web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect. In Jupyter server, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary The `?next=...` URL query parameter has an open redirection vulnerability. In `jupyter_server<=2.17.0`, this URL query parameter allows redirection to arbitrary external domains, which can be exploited to facilitate phishing attacks on server users. ### Details The vulnerability is caused by insufficient validation in the `LoginFormHandler._redirect_safe()` method. - Source code reference: https://github.com/jupyter-server/jupyter_server/blob/987ebdd5e188cdc49751b01a0d6782d686492a53/jupyter_server/auth/login.py#L33-L76 This vulnerability was originally reported by Noriaki Iwasaki. All discovery credit goes to them. ### PoC 1. Navigate to `http://localhost:8888/login?next=///google.com` 2. Observe that the user is redirected to `google.com` despite it being an external domain. The external domain passed in the `?next` parameter may be replaced with a malicious lookalike to facilitate phishing attacks. Jupyter Server deployments served on a public domain are especially vulnerable, as `prod.company.com` may be redirected to a look-alike URL such as `prod.company.dev`. ### Impact This vulnerability affects all users, especially enterprise users who work with sensitive/confidential data. ### Patches Jupyter Server 2.18+ ### Workaround None.

CVE-2025-61669 Affected Jupyter server Versions

1 component(s)
Fixed Versions:
2.18.0
Product / Package Ecosystem Affected Versions Fixed Version
jupyter-server
pypi/jupyter-server
PyPI
< 2.18.0
2.18.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-qh7q-6qm3-653w
NVD — CVE-2025-61669 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-61669
Jupyter server Source Repository REPOSITORY
https://github.com/jupyter-server/jupyter_server
Jupyter server Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server/PYSEC-2026-67.yaml

Frequently Asked Questions

What is CVE-2025-61669?
CVE-2025-61669 is a security vulnerability in Jupyter server involving Jupyter Server has an open redirection vulnerability in `next` query parameter under CWE-601: URL Redirection to Untrusted Site ('Open Redirect').
Which Jupyter server versions are affected?
Affected versions include releases prior to 2.18.0 across affected packages: jupyter-server.
What version fixes CVE-2025-61669?
Upgrading to 2.18.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is jupyter-server affected?
Yes, jupyter-server is affected in releases prior to 2.18.0. Upgrade your dependency to 2.18.0 or later.
What CWE is associated with CVE-2025-61669?
CVE-2025-61669 is classified under CWE-601: URL Redirection to Untrusted Site ('Open Redirect') (The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.).
How can I check PyPI dependencies for CVE-2025-61669?
Run the dependency tree command: 'pip show jupyter-server'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-qh7q-6qm3-653w",
  "modified" : "2026-06-05T17:55:47Z",
  "published" : "2026-05-05T16:32:48Z",
  "aliases" : [ "CVE-2025-61669" ],
  "summary" : "Jupyter Server has an open redirection vulnerability in `next` query parameter",
  "details" : "### Summary\n\nThe `?next=...` URL query parameter has an open redirection vulnerability. In `jupyter_server<=2.17.0`, this URL query parameter allows redirection to arbitrary external domains, which can be exploited to facilitate phishing attacks on server users.\n\n### Details\n\nThe vulnerability is caused by insufficient validation in the `LoginFormHandler._redirect_safe()` method.\n\n- Source code reference: https://github.com/jupyter-server/jupyter_server/blob/987ebdd5e188cdc49751b01a0d6782d686492a53/jupyter_server/auth/login.py#L33-L76\n\nThis vulnerability was originally reported by Noriaki Iwasaki. All discovery credit goes to them.\n\n### PoC\n\n1. Navigate to `http://localhost:8888/login?next=///google.com`\n2. Observe that the user is redirected to `google.com` despite it being an external domain.\n\nThe external domain passed in the `?next` parameter may be replaced with a malicious lookalike to facilitate phishing attacks. Jupyter Server deployments served on a public domain are especially vulnerable, as `prod.company.com` may be redirected to a look-alike URL such as `prod.company.dev`. \n\n### Impact\n\nThis vulnerability affects all users, especially enterprise users who work with sensitive/confidential data.\n\n### Patches\n\nJupyter Server 2.18+\n\n### Workaround\n\nNone.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "jupyter-server"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.17.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-qh7q-6qm3-653w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-61669"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/jupyter-server/jupyter_server"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server/PYSEC-2026-67.yaml"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-601" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-05T16:32:48Z",
    "nvd_published_at" : "2026-05-05T16:16:10Z"
  }
}