Open Redirect in jupyterhub (CVE-2026-33709)
Summary
Vulnerability in jupyterhub (CVE-2026-33709). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.4.4 or later.
Original description
The description as published by the source.
JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks. Prior to version 5.4.4, an open redirect vulnerability in JupyterHub allows attackers to construct links which, when clicked, take users to the JupyterHub login page, after which they are sent to an arbitrary attacker-controlled site outside JupyterHub instead of a JupyterHub page, bypassing JupyterHub's check to prevent this. This issue has been patched in version 5.4.4.
Source: NIST National Vulnerability Database 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-2026-33709 has been found in jupyterhub.
Risk of unauthorized operations or information disclosure. CVSS score: 6.1/10.
What to do: upgrade jupyterhub to 5.4.4 or later.
If unsure, ask your IT team or search "jupyterhub CVE-2026-33709" on the vendor's site.
CVE-2026-33709 (jupyterhub) — CWE-601 / CVSS v3 6.1
Attack vector: remote (network-reachable) / unauthenticated
Patched: 5.4.4 — apply immediately
Workaround: A deployment can apply filters on the Location header in a reverse proxy such as nginx/apache/traefik.
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 jupyterhub.
Check the vendor advisory for the affected versions of jupyterhub.
Severity: Medium (CVSS 6.1/10). Risk of unauthorized operations or information disclosure.
Update to 5.4.4.
Workaround: A deployment can apply filters on the Location header in a reverse proxy such as nginx/apache/traefik.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'jupyterhub' . 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
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1Identify exposure identify
grep -r 'jupyterhub' . | 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
jupyterhubを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
A deployment can apply filters on the Location header in a reverse proxy such as nginx/apache/traefik.パッチが適用されるまでの応急処置として、A deployment can apply filters on the Location header in a reverse proxy such as nginx/apache/traefik. を実施。回避策の副作用 (機能低下) を確認した上で。
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3Apply patch patch
Upgrade jupyterhub to 5.4.4ステージング環境で 5.4.4 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。
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4Post-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-2026-33709 jupyterhub
- Ubuntu UBUNTU-CVE-2026-33709 jupyterhub
References
- advisory github.com
- package github.com
- web github.com
- web nvd.nist.gov