Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix
AV AC AT PR UI VC VI VA CVSS EPSS %ile KEV
N L P L N H H L 7.6 .0058 45.3 —
AFFECTED
Product Versions Fixed
jupyter_server < 2.18.0 – —
TIMELINE
Apr 2 Reserved by GitHub_M
May 5 Published (CNA: GitHub_M)
Jul 24 EXPLOIT PUBLISHED — CVE-2026-35397 (jupyter-server jupyter_server). Public exploit reference added.
Description
Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, a path traversal vulnerability in the REST API allows an authenticated user to escape the configured root_dir and access sibling directories whose names begin with the same prefix as the root_dir. For example, with a root_dir named "test", the API permits access to a sibling directory named "testtest" through a crafted request to the /api/contents endpoint using encoded path components. An attacker can read, write, and delete files in affected sibling directories. Multi-tenant deployments using predictable naming schemes are particularly at risk, as a user with a directory named "user1" could access directories for user10 through user19 and beyond. A user who can choose a single-character folder name could gain access to a significant number of sibling directories.
Version 2.18.0 contains a fix. As a workaround, ensure folder names do not share a common prefix with any sibling directory.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
|---|
| April 2, 2026 | Reserved | Reserved by GitHub_M |
| May 5, 2026 | Published | Published (CNA: GitHub_M) |
| July 24, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-35397 (jupyter-server jupyter_server). Public exploit reference added. |
Affected
Affected products and packages — 1 row
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|
| jupyter-server | jupyter_server | — | < 2.18.0 | — |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-35397 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.