CVE-2023-41333

Workarounds

An admission webhook can be used to prevent the use of endpointSelectors that use the DoesNotExist operator on the reserved:init label in CiliumNetworkPolicies.

Acknowledgements

The Cilium community has worked together with members of Palantir and Isovalent to prepare these mitigations. Special thanks to @odinuge for reporting this issue and @joestringer for the fix.

For more information

If you have any questions or comments about this advisory, please reach out on Slack.

If you think you have found a vulnerability in Cilium, we strongly encourage you to report it to our private security mailing list at [email protected] first, before disclosing it in any public forum. This is a private mailing list for Cilium's internal security team, and your report will be treated as top priority.

An attacker with the ability to create or modify CiliumNetworkPolicy objects in a particular namespace is able to affect traffic on an entire Cilium cluster, potentially bypassing policy enforcement in other namespaces.

By using a crafted endpointSelector that uses the DoesNotExist operator on the reserved:init label, the attacker can create policies that bypass namespace restrictions and affect the entire Cilium cluster. This includes potentially allowing or denying all traffic.

This attack requires API server access, as described in the Kubernetes API Server Attacker section of the Cilium Threat Model.

A critical operation is accessible without requiring any authentication. Typical impact: any user can invoke the privileged function.

CVE-2023-41333 has a CVSS score of 6.9 (Medium). The vector is reachable from an adjacent network, high 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 (1.14.2, 1.13.7, 1.12.14); upgrading removes the vulnerable code path.

Kodem intelligence

This issue was patched in https://github.com/cilium/cilium/pull/28007

This issue affects:

• Cilium <= v1.14.1
• Cilium <= v1.13.6
• Cilium <= v1.12.13

This issue has been resolved in:

• Cilium v1.14.2
• Cilium v1.13.7
• Cilium v1.12.14

1. What is CVE-2023-41333? CVE-2023-41333 is a medium-severity missing authentication for critical function vulnerability in github.com/cilium/cilium (go), affecting versions >= 1.14.0, < 1.14.2. It is fixed in 1.14.2, 1.13.7, 1.12.14. A critical operation is accessible without requiring any authentication.
2. How severe is CVE-2023-41333? CVE-2023-41333 has a CVSS score of 6.9 (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/cilium/cilium are affected by CVE-2023-41333? github.com/cilium/cilium (go) versions >= 1.14.0, < 1.14.2 is affected.
4. Is there a fix for CVE-2023-41333? Yes. CVE-2023-41333 is fixed in 1.14.2, 1.13.7, 1.12.14. Upgrade to this version or later.
5. Is CVE-2023-41333 exploitable, and should I be worried? Whether CVE-2023-41333 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-2023-41333 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-2023-41333?
   • Upgrade github.com/cilium/cilium to 1.14.2 or later
   • Upgrade github.com/cilium/cilium to 1.13.7 or later
   • Upgrade github.com/cilium/cilium to 1.12.14 or later