CVE-2026-56743 Details
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.
A vulnerability in Cilium versions 1.19.0 prior to 1.19.5 allows for unintended ingress traffic from the local namespace when using Kubernetes NetworkPolicy with CIDR-based ipBlock rules that lack pod or namespace selectors. This issue arises when Cilium is configured with a custom cluster name, leading the parser to incorrectly apply a pod selector on selectorless peers. As a result, a wildcard namespace allow rule is generated, permitting traffic from other workloads in the same namespace as the policy's subject.
Users can upgrade to Cilium version 1.19.5, where this issue has been fixed. Alternatively, CiliumNetworkPolicies can be used to achieve the desired effect without encountering this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 16, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-863 | Incorrect Authorization | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| cilium cilium | >= 1.19.0, < 1.19.5 |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 17, 2026 | Initial Analysis | [email protected] |
| Jul 16, 2026 | CVE Modified | CISA-ADP |
| Jul 15, 2026 | New CVE Received | [email protected] |