Bug 1993749 (CVE-2021-25741) - CVE-2021-25741 kubernetes: Symlink exchange can allow host filesystem access
Summary: CVE-2021-25741 kubernetes: Symlink exchange can allow host filesystem access
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-25741
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1993752 1993753 1993754 1993755 1993756
Blocks: 1993750
TreeView+ depends on / blocked
 
Reported: 2021-08-16 05:16 UTC by Sam Fowler
Modified: 2023-02-09 10:29 UTC (History)
26 users (show)

Fixed In Version: kubernetes 1.22.2, kubernetes 1.21.5, kubernetes 1.20.11, kubernetes 1.19.15
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in kubernetes. An authorized user can exploit this by creating pods with crafted subpath volume mounts to access files and directories outside of the volume, including on the host node's filesystem.
Clone Of:
Environment:
Last Closed: 2021-09-28 06:21:07 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:3631 0 None None None 2021-09-27 19:07:02 UTC
Red Hat Product Errata RHSA-2021:3635 0 None None None 2021-09-29 14:24:22 UTC
Red Hat Product Errata RHSA-2021:3642 0 None None None 2021-09-29 11:46:41 UTC
Red Hat Product Errata RHSA-2021:3646 0 None None None 2021-09-30 19:29:03 UTC

Description Sam Fowler 2021-08-16 05:16:20 UTC 
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.

Environments where cluster administrators have restricted the ability to create hostPath mounts are the most seriously affected. Exploitation allows hostPath-like access without use of the hostPath feature, thus bypassing the restriction.

In a default Kubernetes environment, exploitation could be used to obscure misuse of already-granted privileges.
Comment 31 Sam Fowler 2021-09-16 01:45:30 UTC 
Upstream issue:

https://github.com/kubernetes/kubernetes/issues/104980
Comment 34 errata-xmlrpc 2021-09-27 19:07:00 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.8

Via RHSA-2021:3631 https://access.redhat.com/errata/RHSA-2021:3631
Comment 35 Product Security DevOps Team 2021-09-28 06:21:07 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-25741
Comment 36 errata-xmlrpc 2021-09-29 11:46:38 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.6

Via RHSA-2021:3642 https://access.redhat.com/errata/RHSA-2021:3642
Comment 37 errata-xmlrpc 2021-09-29 14:24:21 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.7

Via RHSA-2021:3635 https://access.redhat.com/errata/RHSA-2021:3635
Comment 38 errata-xmlrpc 2021-09-30 19:29:00 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 3.11

Via RHSA-2021:3646 https://access.redhat.com/errata/RHSA-2021:3646
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