CVE-2021-25735

Name	CVE-2021-25735
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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severity	medium
Debian Bugs	990793

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
kubernetes (PTS)	bullseye	1.20.5+really1.20.2-1	fixed
	bookworm, sid	1.20.5+really1.20.2-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
kubernetes	source	bullseye	(not affected)
kubernetes	source	(unstable)	(unfixed)			990793

Notes

[bullseye] - kubernetes <not-affected> (Kubernetes in Bullseye only ships the client)
https://www.openwall.com/lists/oss-security/2021/04/14/1
https://github.com/kubernetes/kubernetes/issues/100096
Server components no longer built since 1.20.5+really1.20.2-1