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MEDIUM · 5.4

CVE-2026-56743

Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors ...

Vulnerability Description

Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.

CVSS Score

5.4

MEDIUM

CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Attack Vector
ADJACENT_NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE

Affected Products

VendorProductVersions
CiliumCilium>= 1.19.0, < 1.19.5

Related Weaknesses (CWE)

CWE-863

References

FAQ

What is CVE-2026-56743?

CVE-2026-56743 is a vulnerability with a CVSS score of 5.4 (MEDIUM). Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors ...

How severe is CVE-2026-56743?

CVE-2026-56743 has been rated MEDIUM with a CVSS base score of 5.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-56743?

Check the references section above for vendor advisories and patch information. Affected products include: Cilium Cilium.