CVE-2026-86258

8.2 HIGH 0.5% exploit odds Fix listed Disclosure

What it is

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.

At a glance

Exploitability: Can be exploited over the network without logging in. High risk of data exposure.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-09-06 13:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-09-10 16:18 UTC Last updatedMost recent change to the record

Details

Published: 2026-09-06 13:17 UTC
Last modified: 2026-09-10 16:18 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-22 · Path traversal
Record status: Awaiting Analysis

Attack profile CVSS 4.0 · 8.2

Attack vector: Network
Complexity: Low
Attack requirements: Present
Privileges needed: None
User interaction: None
Confidentiality: High
Integrity: None
Availability: None

Raw vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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Fix and advisories

https://github.com/jupyter/nbviewer/commit/aad36106f72a1ca7721310c6fccc677ce4c744a5

References

NVD record · CVE.org record