Medium severity · published Sep 6, 2021
CVE-2021-25735
A security issue was discovered in kube-apiserver that could allow node updates to bypass a Validating Admission Webhook
6.5
CVSS
5.4%
EPSS
No
On KEV
Description
A security issue was discovered in kube-apiserver that could allow node updates to bypass a Validating Admission Webhook. Clusters are only affected by this vulnerability if they run a Validating Admission Webhook for Nodes that denies admission based at least partially on the old state of the Node object. Validating Admission Webhook does not observe some previous fields.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)5.4% · higher than 93% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KU
Kubernetes · Kubernetes
before 1.18.18; 1.19.0 before 1.19.10; 1.20.0 before 1.20.6 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-25735
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-25735
Patch
https://github.com/kubernetes/kubernetes/issues/100096
Mailing List
https://groups.google.com/g/kubernetes-security-announce/c/FKAGqT4jx9Y
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