Is CVE-2026-39378 actively exploited?

CVE-2026-39378 has no public evidence of in-the-wild exploitation as of 2026-04-23.

What is the CVSS score for CVE-2026-39378?

CVE-2026-39378 has a CVSS score of 6.5 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N.

How do I patch CVE-2026-39378?

Patch guidance is available from jupyter security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-39378.

CVE-2026-39378 - remediation guidance & executive summary

Description

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Attack Vector: network
Complexity: low
Privileges: none
User Action: required
Scope: unchanged
Confidentiality: high
Integrity: none
Availability: none
Weaknesses: CWE-22 · Path Traversal CWE-73

Metadata

Primary Vendor: JUPYTER
Published: 4/21/2026
Last Modified: 4/23/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2026-39378

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary