CVE-2026-86258

high

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.

References

https://www.vulncheck.com/advisories/nbviewer-through-1.0.1-path-traversal-via-localfilehandler

https://github.com/jupyter/nbviewer/issues/1115

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

https://github.com/jupyter/nbviewer/blob/1.0.1/nbviewer/providers/local/handlers.py#L92-L107

https://github.com/jupyter/nbviewer

Details

Source: Mitre, NVD

Published: 2026-09-06

Updated: 2026-09-06

Risk Information

CVSS v2

Base Score: 5.4

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 5.9

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: Medium

CVSS v4

Base Score: 8.2

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

Severity: High