CVE-2023-6476 is a medium-severity (CVSS 6.5) CWE-770 vulnerability in github.com/cri-o/cri-o. A fix is available for github.com/cri-o/cri-o — see the affected versions and patch details below.
CRI-O's pods can break out of resource confinement on cgroupv2
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-6476.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-6476 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/cri-o/cri-o🐹github.com/cri-o/cri-o🐹github.com/cri-o/cri-oReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
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?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/cri-o/cri-o | ≥ 1.29.0&&< 1.29.1 | 1.29.1go get github.com/cri-o/cri-o@v1.29.1 |
| 🐹Go | github.com/cri-o/cri-o | ≥ 1.28.0&&< 1.28.3 | 1.28.3go get github.com/cri-o/cri-o@v1.28.3 |
| 🐹Go | github.com/cri-o/cri-o | all versions | 1.27.3go get github.com/cri-o/cri-o@v1.27.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cri-o/cri-o, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cri-o/cri-o to 1.29.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-6476 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-6476 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-6476. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
There are two main factors reduce the severity of this vulnerability to Moderate: * A potential attacker must already have valid credentials * The OpenShift environment must already be configured to use an experimental feature
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat OpenShift Container Platform 4.13 | cri-o-0:1.26.4-6.1.rhaos4.13.git9eb9cf3.el8 | RHSA-2024:0195 |
| Red Hat OpenShift Container Platform 4.14 | cri-o-0:1.27.2-7.rhaos4.14.git1cc7a64.el8 | RHSA-2024:0207 |
Frequently Asked Questions
Is CVE-2023-6476 in your dependencies?
O3 Security finds CVE-2023-6476 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.