CVE-2026-39378: jupyter nbconvert Path Traversal
Vulnerability summary
CVE-2026-39378 is a medium (CVSS 6.5) Path Traversal vulnerability in jupyter nbconvert. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 38.5% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 1 · Related 2Timeline
- 21-04-2026PublishedVulnerability first disclosed.
- 21-04-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · PypiEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- OSV · WolfiEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- OSV · ChainguardEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.46%
Chance of exploitation in the next 30 days
Percentile
39%
Versus all other CVEs
30-day change
+0.15 pp
From 0.31% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
- CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.
Affected systems
Chainguard4 products
- datahub-ingestion-fips< 1.5.0.1-r2
- kubeflow-pipelines-visualization-server< 2.16.0-r5
- tensorflow-cpu-jupyter< 2.21.0-r3
- tensorflow-gpu-jupyter< 2.21.0-r3
Debian1 product
- nbconvertAll versions (No fix recorded) | < 7.16.6-1+deb13u1 | < 7.17.1-1
Jupyter1 product
- nbconvert≥ 6.5, < 7.17.1 | ≥ 6.5.0, < 7.17.1
PyPI1 product
- nbconvert≥ 6.5.0, < 7.17.1
Ubuntu1 product
- nbconvertAll versions (No fix recorded)
Wolfi1 product
- kubeflow-pipelines-visualization-server< 2.16.0-r5
6 vendors · 9 products
References
8 links- github.com/jupyter/nbconvert/security/advisories/GHSA-7jqv-fw35-gmx9X Refsource CONFIRMWEBAdvisoryREPORTMitigationVendor Advisory
- github.com/jupyter/nbconvertPACKAGE
