CRI-O's pods can break out of resource confinement on cgroupv2
### 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](https://github.com/cri-o/cri-o/pull/4479) 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](https://github.com/cri-o/cri-o/blob/main/pkg/config/workloads.go#L103-L107) . 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?_
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2023-6476US | high7.5 | — | ||
A flaw was found in CRI-O that involves an experimental annotation leading to a container being unconfined. This may allow a pod to specify and get any amount of memory/cpu, circum… | ||||
references
External citations — patches, advisories, analysis.
- https://access.redhat.com/errata/RHSA-2024:0195WEB
- https://access.redhat.com/errata/RHSA-2024:0207WEB
- https://access.redhat.com/security/cve/CVE-2023-6476WEB
- https://bugzilla.redhat.com/show_bug.cgi?id=2253994WEB
- https://github.com/cri-o/cri-oPACKAGE
- https://github.com/cri-o/cri-o/blob/main/pkg/config/workloads.go#L103-L107WEB
- https://github.com/cri-o/cri-o/commit/75effcb1a25851a736e82dba1f7d8cee93ee159eWEB
- https://github.com/cri-o/cri-o/pull/4479WEB
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