CVE-2021-42952Network attack vector

Authenticated cloud asset access via sandbox escape

Published Feb 25, 2022 · Updated Jul 9, 2026

Sandbox escape in Zepl Notebooks before 2021-10-25 allows remote authenticated users to access internal assets from notebook code. Attacker-controlled code with existing notebook execution escapes the running context sandbox and reaches Zepl resources, including cloud metadata services. Public sources do not identify the sandbox boundary or faulty operation; an authenticated notebook session and initial code execution are required.

CVSS severity9.9
Critical
EPSS probability1.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Sandbox escape in Zepl Notebooks before 2021-10-25 allows remote authenticated users to access internal assets from notebook code. Attacker-controlled code with existing notebook execution escapes the running context sandbox and reaches Zepl resources, including cloud metadata services. Public sources do not identify the sandbox boundary or faulty operation; an authenticated notebook session and initial code execution are required.

The record

CVE
CVE-2021-42952
Published
Feb 25, 2022
Updated
Jul 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1552.005, T1611
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 25, 2022CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.9NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P

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 exploitUnconfirmed

Weakness, pattern, technique

T1552.005Cloud Instance Metadata API
T1611Escape to Host

Public exploit references

No public exploit references are available in this record.

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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