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Vulnerability record · CVE-2021-25741 · published 20 September 2021

CVE-2021-25741: Kubernetes improper input validation vulnerability

Kubernetes · Kubernetes

A security issue was discovered in Kubernetes where a user may be able to create a container with subpath volume mounts to access files & directories outside of the volume, including on the host filesystem.

8.1 CVSS 3.1 High EPSS 8.0% · top 5.4% CWE-20 · Improper input validationCWE-552 · CWE-552
8.1CVSS 3.1 base score, v2 5.5
8.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References
17 Jun 2026Last modified by NVD

Description

A security issue was discovered in Kubernetes where a user may be able to create a container with subpath volume mounts to access files & directories outside of the volume, including on the host filesystem.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/kubernetes/kubernetes/issues/104980 MitigationThird Party Advisory
https://groups.google.com/g/kubernetes-security-announce/c/nyfdhK24H7s Mailing ListMitigation
https://security.netapp.com/advisory/ntap-20211008-0006/ Third Party Advisory
https://github.com/kubernetes/kubernetes/issues/104980 MitigationThird Party Advisory
https://groups.google.com/g/kubernetes-security-announce/c/nyfdhK24H7s Mailing ListMitigation
https://security.netapp.com/advisory/ntap-20211008-0006/ Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2018-1002101Kubernetes vulnerabilityIn Kubernetes versions 1.9.0-1.9.9, 1.10.0-1.10.5, and 1.11.0-1.11.1, user input was handled insecurely while setting up volume mounts on Windows nod…EPSS 4.0%9.8CVE-2018-1002105Kubernetes kube-apiserver proxy upgrade flaw enables backend accessThe kube-apiserver mishandles error responses to proxied upgrade requests, letting a crafted request establish a connection through the API server to…EPSS 87%analysed9.8CVE-2017-1000056Kubernetes missing authorization vulnerabilityKubernetes version 1.5.0-1.5.4 is vulnerable to a privilege escalation in the PodSecurityPolicy admission plugin resulting in the ability to make use…EPSS 2.8%9.8CVE-2016-1906Kubernetes permissions and access controls vulnerabilityOpenshift allows remote attackers to gain privileges by updating a build configuration that was created with an allowed type to a type that is not al…EPSS 4.8%9.6CVE-2017-1002101Kubernetes link following vulnerabilityIn Kubernetes versions 1.3.x, 1.4.x, 1.5.x, 1.6.x and prior to versions 1.7.14, 1.8.9 and 1.9.4 containers using subpath volume mounts with any volum…EPSS 13%8.8CVE-2023-5528Kubernetes improper input validation vulnerabilityA security issue was discovered in Kubernetes where a user that can create pods and persistent volumes on Windows nodes may be able to escalate to ad…EPSS 4.3%8.8CVE-2023-3676Kubernetes improper input validation vulnerabilityA security issue was discovered in Kubernetes where a user that can create pods on Windows nodes may be able to escalate to admin privileges on those…EPSS 13%8.8CVE-2023-3955Kubernetes improper input validation vulnerabilityA security issue was discovered in Kubernetes where a user that can create pods on Windows nodes may be able to escalate to admin privileges on those…EPSS 3.1%

Source: NIST National Vulnerability Database (record CVE-2021-25741), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.