CVE-2026-86258
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- 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
CWEs
CWE-22
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.