CVE-2026-39378

nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding

MEDIUM
6.5
CVSS Score
Published: April 21, 2026 at 12:17 AM UTC
Updated: October 26, 2026 at 09:10 PM UTC
1 product affected across 1 vendorNbconvert

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Severity
MEDIUM6.5
Exploit prediction
EPSS 0.3%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.5.0 ≤ v < 7.17.1
Affected range stops below 7.17.1, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/jupyter/nbconvert/security/advisories/GHSA-7jqv-fw35-gmx9
x_refsource_MISCProduct
Source: cverecord
https://github.com/jupyter/nbconvert/releases/tag/v7.17.1

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-22CWE-73

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