CVE-2026-39377 | BDVDB-2026-328076 Detail

jupyternbconvert

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.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact high, availability impact none. Attack vector: network.

Weaknesses#

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-73 External Control of File Name or Path

References#

Exploit#

No public exploit known

History#

Version 12026-04-21Record published in the CVE List.

Published

Published: 2026-04-21
Last modified: 2026-04-21

Vendor information

Vendor: jupyter
Product: nbconvert

All jupyter vulnerabilities

Score

6.5 Medium

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 18.7.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Path Traversal

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
>= 6.5, < 7.17.1
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

6.5 Medium

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	None
User Interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity	High
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).