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CVE-2023-41333

Bypass of namespace restrictions in CiliumNetworkPolicy

6.9 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Adjacent network
Complexity
Low
Privileges needed
High
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
High

Exploit likelihood

0.48%Up 0.4 points since Sep 27, 2023
90%50%10%1%

What each source reports

CVE List Score used 6.9

Bypass of namespace restrictions in CiliumNetworkPolicy

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.

Record
CVE-2023-41333
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Weakness
CWE-306
Updated
2026-11-02
EUVDEUVD-2023-2423 6.9

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.

Record
EUVD-2023-2423
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-4xp2-w642-7mcx 6.9

Cilium vulnerable to bypass of namespace restrictions in CiliumNetworkPolicy

Impact

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.

Patches

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

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.

Record
GHSA-4xp2-w642-7mcx
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Weakness
CWE-306
Updated
2026-11-02
NVD 6.9

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.

Record
CVE-2023-41333
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
CVSS 3.1
8.1 HighCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:H
Weakness
CWE-306
Updated
2026-11-02
OSV 6.9

Bypass of namespace restrictions in CiliumNetworkPolicy

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.

Record
CVE-2023-41333
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Weakness
CWE-306
Updated
2026-11-02
OSVGHSA-4xp2-w642-7mcx 6.9

Cilium vulnerable to bypass of namespace restrictions in CiliumNetworkPolicy

Impact

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.

Patches

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

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.

Record
GHSA-4xp2-w642-7mcx
CVSS 3.1
6.9 MediumCVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:N/A:H
Weakness
CWE-306
Updated
2026-11-02
Show 8 moreShow less
OSVBIT-cilium-2023-41333 No score

Bypass of namespace restrictions in CiliumNetworkPolicy

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.

Record
BIT-cilium-2023-41333
Updated
2026-11-02
OSVBIT-cilium-operator-2023-41333 No score

Bypass of namespace restrictions in CiliumNetworkPolicy

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.

Record
BIT-cilium-operator-2023-41333
Updated
2026-11-02
OSVBIT-cilium-proxy-2023-41333 No score

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.

Record
BIT-cilium-proxy-2023-41333
Updated
2026-11-02
OSVBIT-hubble-2023-41333 No score

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.

Record
BIT-hubble-2023-41333
Updated
2026-11-02
OSVBIT-hubble-relay-2023-41333 No score

Bypass of namespace restrictions in CiliumNetworkPolicy

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.

Record
BIT-hubble-relay-2023-41333
Updated
2026-11-02
OSVBIT-hubble-ui-2023-41333 No score

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.

Record
BIT-hubble-ui-2023-41333
Updated
2026-11-02
OSVBIT-hubble-ui-backend-2023-41333 No score

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.

Record
BIT-hubble-ui-backend-2023-41333
Updated
2026-11-02
OSVGO-2023-2080 No score

Cilium vulnerable to bypass of namespace restrictions in CiliumNetworkPolicy in github.com/cilium/cilium

Cilium vulnerable to bypass of namespace restrictions in CiliumNetworkPolicy in github.com/cilium/cilium

Record
GO-2023-2080
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/cilium/cilium
Go
 1.14.0 up to 1.14.2
1.14.2
github.com/cilium/cilium
Go
 1.13.0 up to 1.13.7
1.13.7
github.com/cilium/cilium
Go
 before 1.12.14
1.12.14
cilium
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
cilium-operator
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
cilium-proxy
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
hubble
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
hubble-relay
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
hubble-ui
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
hubble-ui-backend
Bitnami
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2
github.com/cilium/cilium
Go
 before 1.12.14, 1.13.0 up to 1.13.7, 1.14.0 up to 1.14.2
1.12.141.13.71.14.2

History

History
RecordedChangedSources
aliases, publishedEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-41333 is a medium vulnerability (CVSS 6.9) in Cilium, published September 26, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.48%, the 41st percentile. Fixed in github.com/cilium/cilium 1.14.2.

References

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