CVE-2026-39378: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in jupyter nbconvert
A path traversal vulnerability exists in jupyter nbconvert versions 6. 5 through 7. 17. 0 when the HTMLExporter. embed_images option is enabled. This flaw allows a malicious notebook to read arbitrary files from the host system by embedding them as base64 data URIs in the converted HTML output. The vulnerability is fixed in version 7. 17. 1. The embed_images option is disabled by default, and avoiding its use mitigates the risk.
AI Analysis
Technical Summary
The vulnerability (CVE-2026-39378) affects jupyter nbconvert, a tool that converts Jupyter notebooks to other formats using Jinja templates. When HTMLExporter.embed_images is set to true, the markdown renderer improperly limits pathnames, allowing path traversal attacks to read arbitrary files on the host system. This enables exfiltration of sensitive files by embedding their contents as base64-encoded images in the HTML output. Versions from 6.5 up to but not including 7.17.1 are affected. The issue is resolved in nbconvert 7.17.1.
Potential Impact
An attacker who can supply a malicious notebook and trigger conversion with embed_images enabled can read arbitrary files on the host system and exfiltrate their contents via the generated HTML. This leads to confidentiality breaches of sensitive data. There is no impact on integrity or availability reported. The vulnerability requires user interaction to convert a crafted notebook and has a medium severity with a CVSS score of 6.5.
Mitigation Recommendations
Upgrade to jupyter nbconvert version 7.17.1 or later, which contains the fix for this vulnerability. As a workaround, do not enable the HTMLExporter.embed_images option, which is disabled by default. Avoid converting untrusted notebooks with embed_images enabled to prevent exploitation.
CVE-2026-39378: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') in jupyter nbconvert
Description
A path traversal vulnerability exists in jupyter nbconvert versions 6. 5 through 7. 17. 0 when the HTMLExporter. embed_images option is enabled. This flaw allows a malicious notebook to read arbitrary files from the host system by embedding them as base64 data URIs in the converted HTML output. The vulnerability is fixed in version 7. 17. 1. The embed_images option is disabled by default, and avoiding its use mitigates the risk.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability (CVE-2026-39378) affects jupyter nbconvert, a tool that converts Jupyter notebooks to other formats using Jinja templates. When HTMLExporter.embed_images is set to true, the markdown renderer improperly limits pathnames, allowing path traversal attacks to read arbitrary files on the host system. This enables exfiltration of sensitive files by embedding their contents as base64-encoded images in the HTML output. Versions from 6.5 up to but not including 7.17.1 are affected. The issue is resolved in nbconvert 7.17.1.
Potential Impact
An attacker who can supply a malicious notebook and trigger conversion with embed_images enabled can read arbitrary files on the host system and exfiltrate their contents via the generated HTML. This leads to confidentiality breaches of sensitive data. There is no impact on integrity or availability reported. The vulnerability requires user interaction to convert a crafted notebook and has a medium severity with a CVSS score of 6.5.
Mitigation Recommendations
Upgrade to jupyter nbconvert version 7.17.1 or later, which contains the fix for this vulnerability. As a workaround, do not enable the HTMLExporter.embed_images option, which is disabled by default. Avoid converting untrusted notebooks with embed_images enabled to prevent exploitation.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-06T21:29:17.350Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69e70c3119fe3cd2cda19912
Added to database: 4/21/2026, 5:33:37 AM
Last enriched: 4/21/2026, 5:33:53 AM
Last updated: 4/21/2026, 7:46:51 AM
Views: 5
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