CVE-2021-21646Network attack vector

Controller code execution via unsandboxed pipeline configuration

Published Apr 21, 2021 · Updated Aug 3, 2024

Code execution in Jenkins Templating Engine Plugin 2.1 and earlier allows remote authenticated users to run code in the controller JVM. PipelineConfigurationDsl evaluates pipeline configuration text with GroovyShell and a custom sandbox instead of Script Security's SecureGroovyScript, allowing unsafe operations to escape its restrictions. Job/Configure permission is required, and successful exploitation grants the Jenkins controller process's privileges.

CVSS severity8.8
High
EPSS probability1.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in Jenkins Templating Engine Plugin 2.1 and earlier allows remote authenticated users to run code in the controller JVM. PipelineConfigurationDsl evaluates pipeline configuration text with GroovyShell and a custom sandbox instead of Script Security's SecureGroovyScript, allowing unsafe operations to escape its restrictions. Job/Configure permission is required, and successful exploitation grants the Jenkins controller process's privileges.

The record

CVE
CVE-2021-21646
Published
Apr 21, 2021
Updated
Aug 3, 2024
Vendor
Jenkins Project
Product
Jenkins Templating Engine Plugin
Classifications
T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

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

  1. Affected versionversion=unspecified <=2.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Jenkins Project · Jenkins Templating Engine Pluginversion=unspecified <=2.1

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 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

T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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