CVE-2021-38834Public exploitNetwork attack vector

Authenticated command execution via vm2 sandbox escape

Published Apr 5, 2022 · Updated Aug 4, 2024

Sandbox escape in Easy Mock 1.5.0 through 1.6.0 allows remote authenticated users to execute arbitrary system commands via crafted mock code. The mock mode evaluator passes attacker-controlled JavaScript to vm2, where a crafted TypeError property retrieves the host Function constructor and reaches process.mainModule.require("child_process").execSync. A low-privileged account that can create and preview a mock can run commands with the Easy Mock service process's permissions.

CVSS severity8.8
High
EPSS probability2.04%
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 Easy Mock 1.5.0 through 1.6.0 allows remote authenticated users to execute arbitrary system commands via crafted mock code. The mock mode evaluator passes attacker-controlled JavaScript to vm2, where a crafted TypeError property retrieves the host Function constructor and reaches process.mainModule.require("child_process").execSync. A low-privileged account that can create and preview a mock can run commands with the Easy Mock service process's permissions.

The record

CVE
CVE-2021-38834
Published
Apr 5, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 5, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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