CVE-2026-6658

mediumpriority · track · 0EPSS 0.002 · 13 %ileEU
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.23% (13th) EPSS
CVSS 5.4 · medium
Is it mine?
1 products
Check your exposure
Who says so?
2 sources
cnnvd · enisa_euvd

EPSS · scored 2026-10-23

A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized `text/vnd.mermaid` output in HTML exports. The `data_mermaid` block in `share/templates/lab/base.html.j2` renders `text/vnd.mermaid` cell output directly into HTML without escaping, enabling attackers to inject arbitrary HTML/JavaScript by breaking out of the `<pre>` tag. This vulnerability impacts any server using nbconvert to render notebooks as HTML, allowing attackers to execute arbitrary JavaScript in the context of users viewing the HTML export.

01

cvss

Technical severity, 0–10. One row per scoring source.

5.4
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.05.4mediumCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · ENISA EU
v3.05.4mediumCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:Nsecondary · security@huntr.devexploitability 2.3 · impact 2.7
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: poc · Automatable: no · Technical Impact: partialcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-79US
04

affected products (1)

Products and version ranges known to be affected.

05

also known as (3)

Other names and identifiers for this entity.

06

sources

Which sources assert this record, and when.

cnnvdenisa_euvdNVDCVE.orgMITRE
published 2026-06-26modified 2026-06-26
07

references (4)

External citations — patches, advisories, analysis.

scry

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