CVE-2021-20218Public exploitNetwork attack vector

Host file overwrite via unnormalized tar paths

Published Mar 16, 2021 · Updated Aug 3, 2024

Path traversal in Fabric8 Kubernetes Client allows remote attackers to write files outside an application's copy destination. PodOperationsImpl joined each tar archive entry name to the destination path without normalizing or rejecting parent-directory segments before extraction. Exploitation requires an application to invoke the client copy command against an attacker-controlled pod or container; crafted entries can overwrite host files and interrupt the application.

CVSS severity7.4
High
EPSS probability1.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Path traversal in Fabric8 Kubernetes Client allows remote attackers to write files outside an application's copy destination. PodOperationsImpl joined each tar archive entry name to the destination path without normalizing or rejecting parent-directory segments before extraction. Exploitation requires an application to invoke the client copy command against an attacker-controlled pod or container; crafted entries can overwrite host files and interrupt the application.

The record

CVE
CVE-2021-20218
Published
Mar 16, 2021
Updated
Aug 3, 2024
Vendor
Fabric8
Product
Fabric8 Kubernetes Client
Classifications
CWE-22, T1565.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 16, 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=kubernetes-client-4.2.0 and after

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Fabric8 · Fabric8 Kubernetes Clientversion=kubernetes-client-4.2.0 and after

Published CVSS scores

7.4NIST NVDCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
5.8NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:P

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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1565.001Stored Data Manipulation

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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