CVE-2025-61669

medium

Published 2026-05-05 · Modified 2026-05-20

CVSS v3

6.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS v2

—

VIR risk

6.1

Description

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.

Predictions

Exploit likelihood

71%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2025-61669

vendor Authored 2026-05-27

Vendor advisory: security-advisories@github.com — https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-qh7q-6qm3-653w

OS impact

OS	Version	Status
debian	bookworm	affected
debian	bullseye	affected
debian	forky	affected
debian	sid	affected
debian	trixie	affected

Package impact

Ecosystem	Package	Vulnerable	Fixed
PyPI	jupyter-server	`<2.18.0`	`2.18.0`
PIP	jupyter-server	`<= 2.17.0`	`2.18.0`

Application impact

Vendor	Product	Versions	Fixed
jupyter	jupyter_server	`{"endExcluding":"2.18.0"}`	`2.18.0`

References

CWEs

CWE-601

Verify integrity in audit chain (admin only). AS-IS.