CVE-2021-32862Public exploitNetwork attack vector

Cross-site scripting via unescaped notebook fields

Published Aug 18, 2022 · Updated Sep 2, 2024

Cross-site scripting in Project Jupyter nbconvert 6.2 and earlier allows remote authenticated users to execute scripts via a crafted notebook. Multiple metadata and output fields are inserted into Jinja HTML templates without escaping, allowing markup to break out of title, attribute, and script contexts. Exploitation requires an attacker-controlled notebook to be converted to HTML and served without a secure content security policy, after which a viewer loads the injected script.

CVSS severity7.5
High
EPSS probability1.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Project Jupyter nbconvert 6.2 and earlier allows remote authenticated users to execute scripts via a crafted notebook. Multiple metadata and output fields are inserted into Jinja HTML templates without escaping, allowing markup to break out of title, attribute, and script contexts. Exploitation requires an attacker-controlled notebook to be converted to HTML and served without a secure content security policy, after which a viewer loads the injected script.

The record

CVE
CVE-2021-32862
Published
Aug 18, 2022
Updated
Sep 2, 2024
Vendor
Project Jupyter
Product
nbconvert
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Project Jupyter · nbconvertversion=<= 6.2

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
7.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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