Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-56743US | —OT elevated | — | ||
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… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8FIX
- https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171FIX
- https://github.com/cilium/cilium/pull/46305FIX
- https://github.com/cilium/cilium/pull/46456FIX
- https://github.com/cilium/cilium/releases/tag/v1.19.5ARTICLE
- https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7rADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-56743WEB
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