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Vulnerability · Published May 5, 2026 · Assigned by GitHub_M

CVE-2025-61669jupyter_server next parameter open redirect can redirect users to external domains

Medium 6.3

In plain English

A medium-severity open redirect in jupyter_server from jupyter-server. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.3Medium
Exploit odds (30 days)0.2%top 84.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.24jupyter-server2.18.2-r0ALPINE-CVE-2025-61669
Debian:12jupyter-serverno fix listedDEBIAN-CVE-2025-61669
Debian:13jupyter-serverno fix listedDEBIAN-CVE-2025-61669
Debian:14jupyter-server2.20.0-1DEBIAN-CVE-2025-61669
PyPIjupyter-server2.18.0PYSEC-2026-67
PyPIjupyter-server2.18.0GHSA-qh7q-6qm3-653w
Ubuntu:22.04:LTSjupyter-serverno fix listedUBUNTU-CVE-2025-61669
Ubuntu:24.04:LTSjupyter-serverno fix listedUBUNTU-CVE-2025-61669
Ubuntu:25.10jupyter-serverno fix listedUBUNTU-CVE-2025-61669
Ubuntu:26.04:LTSjupyter-serverno fix listedUBUNTU-CVE-2025-61669
Ubuntu:26.10jupyter-serverno fix listedUBUNTU-CVE-2025-61669

Affected products (as reported)

VendorProductVersions
jupyter-server jupyter_server <= 2.17.0

Weakness: CWE-601 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

References