How severe is CVE-2021-21646?

CVE-2021-21646 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-21646 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21646?

CVE-2021-21646 affects Jenkins Templating Engine. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21646?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-21646 published?

CVE-2021-21646 was published on 2021-04-21 and last updated on 2026-06-17.

CVE-2021-21646

CVE-2021-21646 is a high-severity vulnerability in Jenkins Templating Engine with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Jenkins Templating Engine
Published: 2021-04-21
Last modified: 2026-06-17

Description

Jenkins Templating Engine Plugin 2.1 and earlier does not protect its pipeline configurations using Script Security Plugin, allowing attackers with Job/Configure permission to execute arbitrary code in the context of the Jenkins controller JVM.

Frequently asked questions

What is CVE-2021-21646?: Jenkins Templating Engine Plugin 2.1 and earlier does not protect its pipeline configurations using Script Security Plugin, allowing attackers with Job/Configure permission to execute arbitrary code in the context of the Jenkins controller JVM.
How severe is CVE-2021-21646?: CVE-2021-21646 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-21646 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21646?: CVE-2021-21646 affects Jenkins Templating Engine. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21646?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21646 published?: CVE-2021-21646 was published on 2021-04-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:jenkins:templating_engine:*:*:*:*:*:jenkins:*:*

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