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CVE-2026-86258

nbviewer through 1.0.1 Path Traversal via LocalFileHandler

CVSS 4.0 8.2 HIGHCVSS 3.1 5.9 MEDIUMCheck source for fixed versionsKEV status unknown

Original advisory

cve-program · CVE-2026-86258

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-86258

Published

nbviewer

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "vendor": "jupyter",
                    "product": "nbviewer",
                    "defaultStatus": "unaffected",
                    "packageURL": "pkg:pypi/nbviewer",
                    "versions": [
                        {
                            "version": "0",
                            "lessThanOrEqual": "1.0.1",
                            "status": "affected",
                            "versionType": "semver"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON