CVE-2026-86258
nbviewer through 1.0.1 Path Traversal via LocalFileHandler
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-22 |
| Vendor | jupyter |
| Product | nbviewer |
| Published | Sep 6, 2026 |
| Last Updated | Sep 10, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
jupyter / nbviewer
0 ≤ 1.0.1
References
github.com: https://github.com/jupyter/nbviewer/issues/1115 github.com: https://github.com/jupyter/nbviewer/blob/1.0.1/nbviewer/providers/local/handlers.py#L92-L107 github.com: https://github.com/jupyter/nbviewer/commit/aad36106f72a1ca7721310c6fccc677ce4c744a5 github.com: https://github.com/jupyter/nbviewer vulncheck.com: https://www.vulncheck.com/advisories/nbviewer-through-1.0.1-path-traversal-via-localfilehandler
Credits
🔍 Yu Sun