CVE-2026-39378

MEDIUM6.5EPSS 0.04%

nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding

Published: 4/21/2026Modified: 4/30/2026

Description

## Summary When `HTMLExporter.embed_images=True`, nbconvert's markdown renderer allows arbitrary file read via path traversal in image references. A malicious notebook can exfiltrate sensitive files from the conversion host by embedding them as base64 data URIs in the output HTML. ## Patches Upgrade to nbconvert 7.17.1 ## Workarounds Do not enable `HTMLExporter.embed_images` (it is not enabled by default).

Affected packages (2)

CVSS scores

SourceVersionSeverityVector
osvCVSS 3.1MEDIUM6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

References (5)