CVE-2026-39378CWE-22CWE-73

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

Medium · published April 21, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
38.6
In the wild
Unconfirmed
What it is

The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. In versions 6.5 through 7.17.0, 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. nbconvert 7.17.1 contains a fix. As a workaround, do not enable `HTMLExporter.embed_images`; it is not enabled by default.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00457 · 38.6th percentile
Weaknesses
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'); CWE-73 · External Control of File Name or Path
Published
2026-04-21T00:17Z
EPSS history
Timeline
  • 21 APR 00:17Z
    nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding
    cvelistv5