Is CVE-2026-39377 actively exploited?

No active exploitation of CVE-2026-39377 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-39377 be exploited remotely?

Yes. CVE-2026-39377 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-39377?

CVE-2026-39377 has a CVSS score of 6.5 (MEDIUM).

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MEDIUM

CVE-2026-39377

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

6.5

CVSS v3.1

EPSS:0.03%probability of exploitation in 30 daysPercentile:9.0th

Official Description

The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. Versions 6.5 through 7.17.0 allow arbitrary file writes to locations outside the intended output directory when processing notebooks containing crafted cell attachment filenames. The `ExtractAttachmentsPreprocessor` passes attachment filenames directly to the filesystem without sanitization, enabling path traversal attacks. This vulnerability provides complete control over both the destination path and file extension. Version 7.17.1 contains a patch.

NVD Source

Technical Analysis

CVE-2026-39377 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 full integrity compromise (data manipulation), with a CVSS base score of 6.5.