CVE-2021-20218

A flaw was found in the fabric8 kubernetes-client in version 4.2.0 and after. This flaw allows a malicious pod/container to cause applications using the fabric8 kubernetes-client `copy` command to extract files outside the working path. The highest threat from this vulnerability is to integrity and system availability. This has been fixed in kubernetes-client-4.13.2 kubernetes-client-5.0.2 kubernetes-client-4.11.2 kubernetes-client-4.7.2

Published: 2021-03-16 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20218 is rated Moderate Risk (53.7/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.31%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20218

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.59% 1.31% +0.72%
2 2025-03-30 0.91% 0.59% -0.32%
3 2025-03-29 — 0.91% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20218

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-20218

GitHub Security Advisory for CVE-2021-20218

GHSA-jwh2-ffg4-48xc · Severity: high · Ecosystem: maven — Improper Limitation of a Pathname to a Restricted Directory in Fabric8 Kubernetes Client

OS Trackers for CVE-2021-20218

vendor priority summary link
redhat medium — https://access.redhat.com/security/cve/CVE-2021-20218

Affected software / configurations for CVE-2021-20218

Vendor Product Version Raw CPE
redhat kubernetes-client >= 4.2.0, < 4.7.2 cpe:2.3:a:redhat:kubernetes-client:*:*:*:*:*:*:*:*
redhat kubernetes-client >= 4.8.0, < 4.11.2 cpe:2.3:a:redhat:kubernetes-client:*:*:*:*:*:*:*:*
redhat kubernetes-client >= 4.12.0, < 4.13.2 cpe:2.3:a:redhat:kubernetes-client:*:*:*:*:*:*:*:*
redhat kubernetes-client >= 5.0.0, < 5.0.2 cpe:2.3:a:redhat:kubernetes-client:*:*:*:*:*:*:*:*
redhat a-mq_online — cpe:2.3:a:redhat:a-mq_online:-:*:*:*:*:*:*:*
redhat build_of_quarkus — cpe:2.3:a:redhat:build_of_quarkus:-:*:*:*:*:*:*:*
redhat codeready_studio 12.0 cpe:2.3:a:redhat:codeready_studio:12.0:*:*:*:*:*:*:*
redhat descision_manager 7.0 cpe:2.3:a:redhat:descision_manager:7.0:*:*:*:*:*:*:*
redhat integration_camel_k — cpe:2.3:a:redhat:integration_camel_k:-:*:*:*:*:*:*:*
redhat jboss_fuse 7.0.0 cpe:2.3:a:redhat:jboss_fuse:7.0.0:*:*:*:*:*:*:*
redhat openshift_container_platform 3.11 cpe:2.3:a:redhat:openshift_container_platform:3.11:*:*:*:*:*:*:*
redhat process_automation 7.0 cpe:2.3:a:redhat:process_automation:7.0:*:*:*:*:*:*:*

References for CVE-2021-20218

cvelogic Threat Intelligence