Open Redirect in jupyter-server (CVE-2025-61669)
Summary
Vulnerability in jupyter-server (CVE-2025-61669). Risk of unauthorized operations or information disclosure. Exploitable via google.com. Mitigation: upgrade to 2.18.0 or later.
Original description
The description as published by the source.
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
- Navigate to
http://localhost:8888/login?next=///google.com - Observe that the user is redirected to
google.comdespite 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.
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-61669 has been found in jupyter-server.
Attackers can target a specific entry point like google.com over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade jupyter-server to 2.18.0 or later.
If unsure, ask your IT team or search "jupyter-server CVE-2025-61669" on the vendor's site.
CVE-2025-61669 (jupyter-server) — CWE-601 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: google.com / prod.company.com / prod.company.dev
Patched: 2.18.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-601) exists in jupyter-server. Attackers reach the vulnerable code path via google.com without authentication.
Check the vendor advisory for the affected versions of jupyter-server. Attack surface: google.com / prod.company.com / prod.company.dev.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 2.18.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'jupyter-server' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'jupyter-server' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
jupyter-serverを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade jupyter-server to 2.18.0ステージング環境で 2.18.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2025-61669 jupyter-server
- Ubuntu UBUNTU-CVE-2025-61669 jupyter-server
References
- advisory nvd.nist.gov
- exploit github.com
- package github.com
- web github.com
- web github.com