CVE-2023-41333

CVE-2023-41333 is a medium-severity vulnerability in Cilium with a CVSS 3.x base score of 6.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Description

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. 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. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. As a workaround an admission webhook can be used to prevent the use of `endpointSelectors` that use the `DoesNotExist` operator on the `reserved:init` label in CiliumNetworkPolicies.

Frequently asked questions

What is CVE-2023-41333?
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. 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. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. As a workaround an admission webhook can be used to prevent the use of `endpointSelectors` that use the `DoesNotExist` operator on the `reserved:init` label in CiliumNetworkPolicies.
How severe is CVE-2023-41333?
CVE-2023-41333 has a CVSS 3.x base score of 6.9, rated medium severity. It is exploitable over an adjacent network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability high.
Is CVE-2023-41333 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-41333?
CVE-2023-41333 affects Cilium. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2023-41333?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2023-41333 published?
CVE-2023-41333 was published on 2023-09-27 and last updated on 2026-06-17.

References

Affected products (1)

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