How severe is CVE-2021-21661?

CVE-2021-21661 has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-21661?

CVE-2021-21661 affects the following packages: org.jenkins-ci.plugins:kubernetes-cli (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-21661?

Update org.jenkins-ci.plugins:kubernetes-cli to 1.10.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21661 is resolved across your whole dependency graph.

How do I detect CVE-2021-21661 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:kubernetes-cli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-21661 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2021-21661 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-21661 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-21661?

CVE-2021-21661 has an EPSS (Exploit Prediction Scoring System) score of 1.6%, placing it in the 76th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2021-21661 published, and has it been updated?

CVE-2021-21661 was published on June 10, 2021 and was last updated on July 8, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2021-21661 — kubernetes-cli

MEDIUM

CVE-2021-21661 is a medium-severity (CVSS 4.3) vulnerability in org.jenkins-ci.plugins:kubernetes-cli. A fix is available for org.jenkins-ci.plugins:kubernetes-cli — see the affected versions and patch details below.

Missing Authorization in Jenkins Kubernetes CLI Plugin

Also known asGHSA-xrg9-wwrq-xmx9

Published

Jun 10, 2021

Updated

Jul 8, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs76th percentile — riskier than 76% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-21661 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

☕org.jenkins-ci.plugins:kubernetes-cli

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Jenkins Kubernetes CLI Plugin 1.10.0 and earlier does not perform permission checks in several HTTP endpoints, allowing attackers with Overall/Read permission to enumerate credentials IDs of credentials stored in Jenkins.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jenkins-ci.plugins:kubernetes-cli`	all versions	1.10.1`org.jenkins-ci.plugins:kubernetes-cli:1.10.1`

Affected Products

1 product · 1 configurations

Application

kubernetesjenkins

≤ 1.10.0

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:kubernetes-cli, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jenkins-ci.plugins:kubernetes-cli to 1.10.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-21661 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-21661 in your dependencies?

Find it across Maven, including transitive dependencies.

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