CVE-2026-86258

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.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/jupyter/nbviewer
https://github.com/jupyter/nbviewer/blob/1.0.1/nbviewer/providers/local/handlers.py#L92-L107
https://github.com/jupyter/nbviewer/commit/aad36106f72a1ca7721310c6fccc677ce4c744a5
https://github.com/jupyter/nbviewer/issues/1115
https://www.vulncheck.com/advisories/nbviewer-through-1.0.1-path-traversal-via-localfilehandler

Configurations

No configuration.

History

No history.

Information

Published : 2026-09-06 13:17

Updated : 2026-09-10 16:18

NVD link : CVE-2026-86258

Mitre link : CVE-2026-86258

CVE.ORG link : CVE-2026-86258

JSON object : View

Products Affected

No product.

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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