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CRI-O's pods can break out of resource confinement on cgroupv2

Moderate severity GitHub Reviewed Published Jan 9, 2024 in cri-o/cri-o • Updated Jan 19, 2024

Package

gomod github.com/cri-o/cri-o (Go)

Affected versions

= 1.29.0
>= 1.28.0, < 1.28.3
< 1.27.3

Patched versions

1.29.1
1.28.3
1.27.3

Description

Impact

What kind of vulnerability is it? Who is impacted?
All versions of CRI-O running on cgroupv2 nodes.
Unchecked access to an experimental annotation allows a container to be unconfined. Back in 2021, support was added to support an experimental annotation that allows a user to request special resources in cgroupv2. It was supposed to be gated by an experimental annotation: io.kubernetes.cri-o.UnifiedCgroup, which was supposed to be filtered from the list of allowed annotations . However, there is a bug in this code which allows any user to specify this annotation, regardless of whether it's enabled on the node. The consequences of this are a pod can specify any amount of memory/cpu and get it, circumventing the kubernetes scheduler, and potentially be able to DOS a node.

Patches

Has the problem been patched? What versions should users upgrade to?
1.29.1, 1.28.3, 1.27.3

Workarounds

Is there a way for users to fix or remediate the vulnerability without upgrading?
use cgroupv1

References

Are there any links users can visit to find out more?

References

@haircommander haircommander published to cri-o/cri-o Jan 9, 2024
Published by the National Vulnerability Database Jan 9, 2024
Published to the GitHub Advisory Database Jan 10, 2024
Reviewed Jan 10, 2024
Last updated Jan 19, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.058%
(25th percentile)

Weaknesses

CVE ID

CVE-2023-6476

GHSA ID

GHSA-p4rx-7wvg-fwrc

Source code

Credits

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