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🛡️ CVE-2021-32797 — jupyterlab

🔴 CVSS 9.5 — Critical ✅ No Known Exploit CWE-75 OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

JupyterLab: XSS due to lack of sanitization of the action attribute of an html <form>

Impact

Untrusted notebook can execute code on load. This is a remote code execution, but requires user action to open a notebook.

Patches

Patched in the following versions: 3.1.4, 3.0.17, 2.3.2, 2.2.10, 1.2.21.

References

[OWASP Page on Restricting Form Submissions](https://cheatsheetseries.owasp.org/cheatsheets/Content_Security_Policy_Cheat_Sheet.html)

For more information

If you have any questions or comments about this advisory, or vulnerabilities to report, please email our security list [email protected].

Credit: Guillaume Jeanne from Google

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. A user must be tricked into taking some action. Rated impact: confidentiality none, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Attack requirements: None — no deployment-specific condition has to hold.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: Passive — a victim action is involved, but not a deliberate one.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2021-32797 is classified as CWE-75: Failure to Sanitize Special Elements into a Different Plane (Special Element Injection). The product does not adequately filter user-controlled input for special elements with control implications.

Affected software

CVE-2021-32797 is recorded against 2 packages.

  • jupyterlab (from 3.1.0a0 up to 3.1.4)
  • notebook (from 6.0.0 up to 6.4.1)

Timeline and source

Published on 23 August 2021 and last revised on 8 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
github.com (Web)
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)

Other advisories for this package

jupyterlab has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-75: Failure to Sanitize Special Elements into a Different Plane (Special Element Injection)) in other software:

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N
CWE CWE-75
Public Exploit ✅ No
Source OSV
Published 2021-08-23
Updated 2026-08-20
Modified 2026-07-08
Fix URL N/A

Affected Packages

Software From version Fixed in
jupyterlab 3.1.0a0 3.1.4
notebook 6.0.0 6.4.1

Exploit Protection

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CVE-2021-32797 carries CVSS 9.5 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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