Vulnerability in jupyter-server (CVE-2026-5422)
Summary
Vulnerability in jupyter-server (CVE-2026-5422). Confidential information can be exposed externally. Mitigation: upgrade to 2.18.2 or later.
Original description
The description as published by the source.
A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip ".." from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.
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-2026-5422 has been found in jupyter-server.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade jupyter-server to 2.18.2 or later.
If unsure, ask your IT team or search "jupyter-server CVE-2026-5422" on the vendor's site.
CVE-2026-5422 (jupyter-server) — CWE-23 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Patched: 2.18.2 — 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-23) exists in jupyter-server.
Check the vendor advisory for the affected versions of jupyter-server.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to 2.18.2.
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
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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 2.18.2ステージング環境で 2.18.2 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-2026-5422 jupyter-server
- Ubuntu UBUNTU-CVE-2026-5422 jupyter-server
References
- advisory nvd.nist.gov
- advisory github.com
- advisory github.com
- package github.com
- web huntr.com
- web github.com
- web github.com
- web pypi.org