CVE-2026-39377
nbconvert has an Arbitrary File Write via Path Traversal in Cell Attachment Filenames
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-22 CWE-73 |
| Vendor | jupyter |
| Product | nbconvert |
| Published | Apr 21, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Affected Versions
jupyter / nbconvert
>= 6.5, < 7.17.1