Is CVE-2026-39378 actively exploited?

No active exploitation of CVE-2026-39378 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-39378 be exploited remotely?

Yes. CVE-2026-39378 is exploitable remotely over the network (CVSS attack vector: Network).

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

CVE-2026-39378 has a CVSS score of 6.5 (MEDIUM).

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MEDIUM

CVE-2026-39378

CWE-22Published: April 21, 2026· Updated: Apr 23, 2026

6.5

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:10.9th

Official 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.

NVD Source

Technical Analysis

CVE-2026-39378 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 6.5.