# CVE-2026-39378: nbconvert: The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates

CVE-2026-39378 is fixed in nbconvert on 1 platform, first by DEBIAN-CVE-2026-39378, released May 15, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-39378
- Priority: Routine
- CVSS: 6.5 (medium)
- EPSS: 0.0031
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 21, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nbconvert Debian 13.5 (trixie) | 7.16.6-1+deb13u1 | [DEBIAN-CVE-2026-39378](https://patchblox.com/security/data/fix/linux/debian-cve-2026-39378.md) | May 15, 2026 |
| Linux | nbconvert Debian 14 | 7.17.1-1 | [DEBIAN-CVE-2026-39378](https://patchblox.com/security/data/fix/linux/debian-cve-2026-39378.md) | May 15, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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