CVE-2026-86258
nbviewer through 1.0.1 Path Traversal via LocalFileHandler
- State
- Published
- Severity
- 8.2 High
- Published
- Sep 6, 2026
- Updated
- Sep 24, 2026
- Reserved
- Sep 6, 2026
Description
nbviewer through 1.0.1 contains a path traversal vulnerability in LocalFileHandler.can_show() that uses string-prefix comparison instead of proper path validation. Attackers can read files from sibling directories outside the configured root by requesting paths that share the root as a textual prefix, disclosing unintended notebooks and credentials.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.2 High | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 5.9 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N | VulnCheck |
Weaknesses
- CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Affected Products
| Product | Versions |
|---|---|
nbviewerjupyter |
|
References
- GitHub Issue #1115issue-tracking
- LocalFileHandler.can_show() at 1.0.1technical-description
- Fix path-containment bypass in LocalFileHandler.can_show (PR #1116)patch
- https://github.com/jupyter/nbviewerproduct
- VulnCheck Advisory: nbviewer through 1.0.1 Path Traversal via LocalFileHandlerthird-party-advisory
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