Answer in brief
CVE-2026-35397 records a High severity (CVSS 8.8) vulnerability in jupyter-server path traversal allows access to sibling directories sharing root_dir name prefix. The current sources do not mark it as known exploited. The current feed maps jupyter-server/jupyter_server (generic), jupyter-server (pip), jupyter-server (pypi). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps jupyter-server/jupyter_server (generic), jupyter-server (pip), jupyter-server (pypi). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:jupyter:jupyter_server:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| jupyter-server/jupyter_servergeneric | < 2.18.0 | Not reported |
| jupyter-serverpip | <=2.17.0 | 2.18.0 |
| jupyter-serverpypi | >=0 <2.18.0 | 2.18.0 |
Published upstream
May 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.