CVE-2023-6476

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?

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.

Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service. Typical impact: denial of service.

CVE-2023-6476 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.29.1, 1.28.3, 1.27.3); upgrading removes the vulnerable code path.

Kodem intelligence

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

1. What is CVE-2023-6476? CVE-2023-6476 is a medium-severity uncontrolled resource consumption vulnerability in github.com/cri-o/cri-o (go), affecting versions = 1.29.0. It is fixed in 1.29.1, 1.28.3, 1.27.3. Crafted input forces the application to consume excessive CPU, memory, or other resources, degrading or denying service.
2. How severe is CVE-2023-6476? CVE-2023-6476 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/cri-o/cri-o are affected by CVE-2023-6476? github.com/cri-o/cri-o (go) versions = 1.29.0 is affected.
4. Is there a fix for CVE-2023-6476? Yes. CVE-2023-6476 is fixed in 1.29.1, 1.28.3, 1.27.3. Upgrade to this version or later.
5. Is CVE-2023-6476 exploitable, and should I be worried? Whether CVE-2023-6476 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-6476 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-6476?
   • Upgrade github.com/cri-o/cri-o to 1.29.1 or later
   • Upgrade github.com/cri-o/cri-o to 1.28.3 or later
   • Upgrade github.com/cri-o/cri-o to 1.27.3 or later