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BREW-jupyterlab-CVE-2025-61669 — Jupyter Server has an open redirection vulnerability in `next` query parameter

Affected: Homebrew: jupyterlab

### 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.

Withdrawn: CLEANSTART-2026-GG76429 — Security fixes in tensorflow-gpu-jupyter 2.21.0-r5

Withdrawn by the publisher.

Affected: CleanStart: tensorflow-gpu-jupyter

Package tensorflow-gpu-jupyter version 2.21.0-r5 fixes 28 vulnerabilities: ghsa-rch3-82jr-f9w9, ghsa-mqcg-5x36-vfcg, ghsa-37w4-hwhx-4rc4, ghsa-mf9v-mfxr-j63j, ghsa-5mrq-x3x5-8v8f...

EUVD-2026-308644

fkie_cve-2025-61669

Jupyter Server is the backend for Jupyter web applications. In jupyter_server versions through 2.17.0, the next query parameter in the login flow is insufficiently validated in `LoginFormHandler._redirect_safe()`, which allows redirects to arbitrary external domains via values such as `///example.com`. An attacker can use a crafted login URL to redirect users to a malicious site and facilitate phishing attacks. This issue is fixed in version 2.18.0.

GHSA-qh7q-6qm3-653w — Jupyter Server has an open redirection vulnerability in `next` query parameter

Affected: PyPI: jupyter-server

### Summary

### 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.

### Impact

This vulnerability affects all users, especially enterprise users who work with sensitive/confidential data.

### Patches

Jupyter Server 2.18+

### Workaround

None.

jvndb-2026-000080

Jupyter Server provided by Jupyter Development Team contains the vulnerability listed below.<a href='https://cwe.mitre.org/data/definitions/601.html' target='_blank'></a><ul><li>Open redirect (CWE-601) - CVE-2025-61669</li></ul>Noriaki Iwasaki of Cyber Defense Institute, Inc. reported this vulnerability to IPA and the developer. JPCERT/CC coordinated with the developer to publish the advisory under Information Security Early Warning Partnership.

OESA-2026-4080 — python-jupyter-server security update

Affected: openEuler:24.03-LTS-SP4: python-jupyter-server

The backend for Jupyter web applications Security Fix(es):

Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, a path traversal vulnerability in the REST API allows an authenticated user to escape the configured root_dir and access sibling directories whose names begin with the same prefix as the root_dir. For example, with a root_dir named "test", the API permits access to a sibling directory named "testtest" through a crafted request to the /api/contents endpoint using encoded path components. An attacker can read, write, and delete files in affected sibling directories. Multi-tenant deployments using predictable naming schemes are particularly at risk, as a user with a directory named "user1" could access directories for user10 through user19 and beyond. A user who can choose a single-character folder name could gain access to a significant number of sibling directories.

Version 2.18.0 contains a fix. As a workaround, ensure folder nam…

openSUSE-SU-2026:10710-1 — python311-jupyter-server-2.18.1-1.1 on GA media

python311-jupyter-server-2.18.1-1.1 on GA media

PYSEC-2026-67

Affected: PyPI: jupyter-server

UBUNTU-CVE-2025-61669

Affected: Ubuntu:22.04:LTS: jupyter-server, Ubuntu:24.04:LTS: jupyter-server, Ubuntu:25.10: jupyter-server, Ubuntu:26.04:LTS: jupyter-server