nbconvert has an Arbitrary File Write via Path Traversal in Cell Attachment Filenames
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · High · None
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| jupyterlab | nbconvert | 6.5 to before 7.17.1 | 7.17.1 | Patch available | CNA |
| — | nbconvert (PyPI) | 6.5.0 to before 7.17.1 | 7.17.1 | Patch available | GHSA-4c99-qj7h-p3vg |
- nbconvert Vendorjupyterlab Affected 6.5 to before 7.17.1 Fixed in 7.17.1 Patch available CNA
- nbconvert (PyPI) Vendor— Affected 6.5.0 to before 7.17.1 Fixed in 7.17.1 Patch available GHSA-4c99-qj7h-p3vg
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:jupyter:nbconvert:*:*:*:*:*:python:*:* | 6.5.0 to before 7.17.1 | Vulnerable | jupyterlab |
- cpe:2.3:a:jupyter:nbconvert:*:*:*:*:*:python:*:* Versions 6.5.0 to before 7.17.1 Vulnerable ·jupyterlab
Remediation
- Fix · CNA nbconvert (jupyter) Fixed in 7.17.1
- Fix · GHSA-4c99-qj7h-p3vg nbconvert (PyPI) Fixed in 7.17.1 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Migration Toolkit for Applications 8 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift AI (RHOAI) | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Satellite 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-39377
- 2026-10-03 Alias added: GHSA-4c99-qj7h-p3vg
References
More jupyterlab Nbconvert vulnerabilities
- TI-2025-33005 nbconvert has an uncontrolled search path that leads to unauthorized code execution on Windows CVSS 4.0HIGH 8.5
- TI-2021-12526 nbconvert vulnerable to cross-site scripting (XSS) via multiple exploit paths CVSS 3.1HIGH 7.5
- TI-2026-28364 nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding CVSS 3.1MEDIUM 6.5
Sources
- CVE-2026-39377 · CVE Program
- CVE-2026-39377 · NVD
- FIRST EPSS
- GHSA-4c99-qj7h-p3vg · GitHub Advisory Database · CC BY 4.0
- CVE-2026-39377 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences