CVE-2026-86258
High · CVSS 8.2Published 2026-09-06
CVSS
8.2
High
EPSS
—
exploit probability
Active Exploit
No
not yet listed
What is 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 Score Explained
CVSS 8.2 is High severity. Exploitation is likely straightforward and the impact is significant — data loss, privilege escalation, or remote code execution are common outcomes. Patch as soon as possible.
EPSS Exploitation Probability
No EPSS score yet — model needs more data on this CVE.
References & Patches
- ›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
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