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CVE Record

CVE-2018-19351: Jupyter Notebook before 5.7.1 allows XSS via an untrusted notebook because nbconvert responses are consider...

Jupyter Notebook before 5.7.1 allows XSS via an untrusted notebook because nbconvert responses are considered to have the same origin as the notebook server. In other words, nbconvert endpoints can execute JavaScript with access to the server API. In notebook/nbconvert/handlers.py, NbconvertFileHandler and NbconvertPostHandler do not set a Content Security Policy to prevent this.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

Jupyter Notebook before 5.7.1 could let an untrusted notebook run JavaScript as if it belonged to the notebook server. That matters because the script could access the server API in the user’s browser context. The sources do not provide CVSS, confirmed exploitation, or broad product inventory details.

Executive priority

Treat this as a meaningful developer and data-platform risk, not an internet-wide emergency based on the provided evidence. Prioritize upgrades where Jupyter handles shared, external, or untrusted notebooks.

Technical view

The issue is an XSS flaw in Jupyter Notebook nbconvert handling. NbconvertFileHandler and NbconvertPostHandler did not set a Content Security Policy, so nbconvert responses shared the notebook server origin and could execute JavaScript with server API access. The CVE states versions before 5.7.1 are affected.

Likely exposure

Exposure is most likely where Jupyter Notebook versions before 5.7.1 are used and users open or render untrusted notebooks. Risk increases if notebook servers are reachable by many users or exposed beyond a trusted local environment.

Exploitation context

The bundle does not show CISA KEV listing or confirmed active exploitation. Public references describe the vulnerability class, affected version boundary, upstream commit, release history, changelog, and a Debian LTS security update.

Researcher notes

Root cause is same-origin trust for nbconvert output without a protective CSP in notebook/nbconvert/handlers.py. The key validation target is whether affected handlers include the upstream fix or vendor backport, not just package naming.

Mitigation direction

  • Upgrade Jupyter Notebook to 5.7.1 or later.
  • Apply distribution security updates, including Debian’s jupyter-notebook update where relevant.
  • Restrict notebook server access to trusted users and networks.
  • Avoid opening or converting untrusted notebooks until patched.
  • Check upstream and distribution guidance for environment-specific instructions.

Validation and detection

  • Inventory installed notebook package versions across developer, data science, and server environments.
  • Flag any Jupyter Notebook installation older than 5.7.1.
  • Confirm patched packages include the upstream nbconvert CSP fix.
  • Review whether notebook servers are exposed beyond trusted local access.
  • Check workflows that import, open, or convert notebooks from untrusted sources.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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