How severe is CVE-2023-41333?

CVE-2023-41333 has a CVSS score of 6.9/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-41333?

CVE-2023-41333 affects the following packages: github.com/cilium/cilium (Go), github.com/cilium/cilium (Go), github.com/cilium/cilium (Go). Ecosystems affected: Go.

How do I fix CVE-2023-41333?

Update github.com/cilium/cilium to 1.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-41333 is resolved across your whole dependency graph.

How do I detect CVE-2023-41333 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cilium/cilium, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2023-41333 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2023-41333 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-41333 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2023-41333?

CVE-2023-41333 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2023-41333?

CVE-2023-41333 is classified as Missing Authentication (CWE-306). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2023-41333 published, and has it been updated?

CVE-2023-41333 was published on September 26, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2023-41333 — cilium

MEDIUMFix: cilium/cilium#28007

CVE-2023-41333 is a medium-severity (CVSS 6.9) Missing Authentication vulnerability in github.com/cilium/cilium. A fix is available for github.com/cilium/cilium — see the affected versions and patch details below.

Bypass of namespace restrictions in CiliumNetworkPolicy

Also known asBIT-cilium-2023-41333BIT-cilium-operator-2023-41333BIT-cilium-proxy-2023-41333BIT-hubble-2023-41333BIT-hubble-relay-2023-41333BIT-hubble-ui-2023-41333

Published

Sep 26, 2023

Updated

Oct 28, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 29, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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-2023-41333.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐹github.com/cilium/cilium🐹github.com/cilium/cilium🐹github.com/cilium/cilium

Real-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

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.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/cilium/cilium`	≥ 1.14.0&&< 1.14.2	1.14.2`go get github.com/cilium/cilium@v1.14.2`
🐹Go	`github.com/cilium/cilium`	≥ 1.13.0&&< 1.13.7	1.13.7`go get github.com/cilium/cilium@v1.13.7`
🐹Go	`github.com/cilium/cilium`	all versions	1.12.14`go get github.com/cilium/cilium@v1.12.14`

Affected Products

1 product · 3 configurations

Application

ciliumcilium

≥ 1.14.0 && < 1.14.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/cilium/cilium, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cilium/cilium to 1.14.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-41333 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### 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](ht