Vulnerability · Published Jun 2, 2026 · Assigned by @huntr_ai
CVE-2026-5422Path Traversal in jupyter/jupyter
Medium 6.8
In plain English
A medium-severity security flaw in jupyter/jupyter from jupyter. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 4.9% (higher than 92% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | jupyter-server | no fix listed | DEBIAN-CVE-2026-5422 |
| Debian:13 | jupyter-server | no fix listed | DEBIAN-CVE-2026-5422 |
| Debian:14 | jupyter-server | no fix listed | DEBIAN-CVE-2026-5422 |
| PyPI | jupyter-server | 2.18.2 | GHSA-gf7q-q4j7-hp7c |
| PyPI | jupyter-server | 2.18.2 | PYSEC-2026-2532 |
| Ubuntu:22.04:LTS | jupyter-server | no fix listed | UBUNTU-CVE-2026-5422 |
| Ubuntu:24.04:LTS | jupyter-server | no fix listed | UBUNTU-CVE-2026-5422 |
| Ubuntu:25.10 | jupyter-server | no fix listed | UBUNTU-CVE-2026-5422 |
| Ubuntu:26.04:LTS | jupyter-server | no fix listed | UBUNTU-CVE-2026-5422 |
| Ubuntu:26.10 | jupyter-server | no fix listed | UBUNTU-CVE-2026-5422 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| jupyter | jupyter/jupyter | unspecified – through latest |
Weakness: CWE-23 · Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N